Well, you started with glass tile and you ended with glass tile. Don't see why they would be charging you more (twice) seeing as they aren't anywhere near the tile installation yet and its no difference to them from what they quoted you originally.
I can tell you that the owner of the company building our pool stopped by today to check progress and chat. She said the supply chain issues are real and you either pay the increase in prices or the job doesn’t get done. She mentioned that the 5 pallets of travertine pavers, they delivered yesterday, is costing them three times the amount from when we signed in March. She also told us that she is aware of at least 5 pool builders that are closing up shop, at the end of the year, because they will not be able to get supplies for next years builds.