Wow - that is tough! I'd be unhappy if I'd made the journey, I do feel for you. However, and without wishing to be selfish here.... Tile Mountain have been good about it with me. No quibbles, they refunded me the MP90 immediately. Of course we hadn't used it yet so there was no labour costs for cleaning up any mess, but nevertheless they didn't hang around, they even volunteered to refund it themselves.
I suppose the other difference may be that the manufacturer of your tiles may have agreed that they needed sealing. You might contact them to see what they say - their name will be on the tile box. If they say that, categorically, the tiles should not be sealed then you may have a better case to take to the retailer to get your cash back for the sealer and the cleaner I would think. In my case, the manufacturer sent me (and Tile Mountain) an email within an hour or two of me asking the question, stating clearly that the tiles should not be sealed. So full marks all around, as far as I am concerned. The manufacturer has given a cast-iron statement that the tiles do not need sealing, and tile mountain has refunded me immediately for the sealer that their website told me I needed. I appreciate your experience has not been as good, but credit where it is due, Tile Mountain righted the wrong quickly and without complaint in my case.
However now that we are not sealing the tiles, I am a bit concerned about the grout. I've got them in a wet room shower. BAL tell me not to worry and that their micromax doesn't need sealing, but we used that in the other bathroom and it does discolour over time. Oh well. I am sure there is another world of detail around grout cleaning chemicals that i will learn about in the next year or so.
Honestly, every time I take on a tiling project I am amazed at the level of complexity involved and knowledge needed to do it right. And I wasn't even laying the tiles this time, and they are basic porcelain tiles! I dread to think what percentage of installations are done with some error somewhere that would invalidate any warranty. No wonder the tile companies have technical support hotlines!