The answers you go should have given you a clue to what you need to do. If the tile was discontinued more than 2 years ago then you need to consider a new ceiling. If less than two years then you need contact the local distributor and make a deal with them first. The have them furnish all of the phone numbers and contact information to all of the other distributors in the country................... let your fingers do the walking. ............. Sure is not going to be easy..
I had the same problem with some tile that I bought. A couple of boxes were broken upon opening the boxes. I needed 12 pieces to finish. I got a hold of all the places that sold the tile and told them I would buy all that they had. I found 15 tiles in 3 places. One was a 4 hour drive from my home. Took me several weeks. I was considering starting over. Tile was not all that expensive in fact most stores sold it to me at less than I paid for it new.
Luck of the Irish to you