See especially section 2-608, below. The whole section is relevant, and pretty much says what I have said.
Copy to the OP with the reminder that I'm going by what he said, and assuming he didn't leave out anything important.
It does seem hard to believe that they would behave the way the OP describes since they are so sure to lose. But the catch here is that "they" didn't do anything. Things are done by one, two, or three people, who aren't always as reasonable or as informed as their bosses would want.
Maybe the OP was combative on the phone with the main office, and the person retaliated by brushing him off, maybe by not even listening to whether his complaint was valid. Maybe lots of things.
And maybe the op would lose because he loses the contract or the receipt or has no evidence about what they sent, or what he wanted. Etc. Suing is a pain in the neck, but when one wins, it feels real good. Also, be willing to let them make amends after you file suit but before the trial. In many cases, especially landlord tenant, one cannot accept the assurance of the other party that they are dropping the case. Landlords have been known to accept the rent, or partial rent according to their calculations and leave a tenant with the impression that everything is settled. Meanwhile, they go to court, the tenant doesn't, and the ll receives a default eviction order. Here though, if he has his washer in his house, he's probably safe, especially since he was the plaintiff, and he would have to be notified if a counter suit had been filed.
So, based
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This is not directly on point, and I only offer it because it uses the term "justifiably revokes acceptance". So there are times when one can justifiably revoke acceptance.
§ 2-712. "Cover"; Buyer's Procurement of Substitute Goods.
(1) If the seller wrongfully fails to deliver or repudiates or the buyer rightfully rejects or justifiably revokes acceptance, the buyer may .....
This is from the Uniform Commercial Code. There have been uniform codes written on most parts of the law, but the UCC is the most accepted. It has been enacted in all 50 states, or maybe it was 49, and a few states have made a few changes, but almost the entire code is in effect in all 49 or 50 states. I think that is possible because there aren't too many emotional issues regarding commerce, and because it makes interstate commerce a lot easier when there is no conflict of laws. Every state legistlature wants its state to fully participate in interstate commerce.
The online version I'm citing doesn't include notes, because it says, it's license doesn't permit displaying notes. Reading the notes would help to understand things, and might give a case on point or close, but I don't think it's necessary.
Here is another relevant section that one can reach by . It has to be read as a whole, because it can be misleading to cite just one sentence without looking at the rest. Also one must know all the relevant laws including those not in the UCC or it can be misleading. That's why others are lawyers and we're not. But here is this part.
See especially section 2-608. The whole section is relevant:
"§ 2-607. Effect of Acceptance; Notice of Breach; Burden of Establishing Breach After Acceptance; Notice of Claim or Litigation to Person Answerable Over.
(1) The buyer must pay at the contract rate for any goods accepted.
(2) Acceptance of goods by the buyer precludes rejection of the goods accepted and if made with knowledge of a non-conformity cannot be revoked because of it unless the acceptance was on the reasonable assumption that the non-conformity would be seasonably cured but acceptance does not of itself impair any other remedy provided by this Article for non-conformity.
(3) Where a tender has been accepted
(a) the buyer must within a reasonable time after he discovers or should have discovered any breach notify the seller of breach or be barred from any remedy; and
(b) [definitely not relevant imo] if the claim is one for infringement or the like (subsection (3) of Section 2-312) and the buyer is sued as a result of such a breach he must so notify the seller within a reasonable time after he receives notice of the litigation or be barred from any remedy over for liability established by the litigation.
(4) The burden is on the buyer to establish any breach with respect to the goods accepted.
(5) Where the buyer is sued for breach of a warranty or other obligation for which his seller is answerable over
(a) he may give his seller written notice of the litigation. If the notice states that the seller may come in and defend and that if the seller does not do so he will be bound in any action against him by his buyer by any determination of fact common to the two litigations, then unless the seller after seasonable receipt of the notice does come in and defend he is so bound.
(b) if the claim is one for infringement or the like (subsection (3) of Section 2-312) the original seller may demand in writing that his buyer turn over to him control of the litigation including settlement or else be barred from any remedy over and if he also agrees to bear all expense and to satisfy any adverse judgment, then unless the buyer after seasonable receipt of the demand does turn over control the buyer is so barred.
(6) The provisions of subsections (3), (4) and (5) apply to any obligation of a buyer to hold the seller harmless against infringement or the like (subsection (3) of Section 2-312).
§ 2-608. Revocation of Acceptance in Whole or in Part.
(1) The buyer may revoke his acceptance of a lot or commercial unit whose non-conformity substantially impairs its value to him if he has accepted it
(a) on the reasonable assumption that its non-conformity would be cured and it has not been seasonably cured; or
(b) without discovery of such non-conformity if his acceptance was reasonably induced either by the difficulty of discovery before acceptance or by the seller's assurances.
(2) Revocation of acceptance must occur within a reasonable time after the buyer discovers or should have discovered the ground for it and before any substantial change in condition of the goods which is not caused by their own defects. It is not effective until the buyer notifies the seller of it.
(3) A buyer who so revokes has the same rights and duties with regard to the goods involved as if he had rejected them.
(4) If a buyer uses the goods after a rightful rejection or justifiable revocation of acceptance, the following rules apply:
(a) Any use by the buyer that is unreasonable under the circumstances is wrongful as against the seller and is an acceptance only if ratified by the seller.
(b) Any use of the goods that is reasonable under the circumstances is not wrongful as against the seller and is not an acceptance, but in an appropriate case the buyer is obligated to the seller for the value of the use to the buyer."