One of the problems I get is that if the call centre is abroad, they hand off to a robot which means you have to key everything in via a keypad. This usually fails as who the heck manages to key in the whole of the card number in one go and without errors with such a short time delay between numbers.
I won't deal with companies that do this, and gradually they seem to be noting that this simply won't work for most people and they have to relent and have one certified person in the organisation who can do it. I guess this is because that a bunch of foreign call centre staff cannot be trusted with card details.
Fraud seems to be far more of an issue than it used to be. I ran into a problem last week where my chip and signature card was not able to work in a shop, even though the law says it should. If the keypad for a pin was a proper pad with a bump on the 5 then fine, but most of the new ones are flat glass panels which blind people cannot use. For 26 quid I paid in cash, but I did point out to them that their system was illegal, which they acknowledge, but said that the terminals were supplied by their bank and they could not do anything about it. Pass the hand grenade matey... Brian