Use a ph neutral cleaner. I'll guarantee you that same tile store will be able to get you one from one of the sealer companies.

And I thought I did bad work after drinking a case of beer and not sleeping for three days. While splitting my work hours with one eye on the tiling job and two eyes on the portable TV I brought to work with me so I could watch playoff baseball. All while minding my three toddlers that I had to bring on the job because I forgot where their daycare was located. While blind in one eye. And with my left arm in a cast and my right arm in a sling. While working barefoot. On an empty stomach. Okay. My question to him is "why" does he feel that this is the best that can be done? If it's because he has limited talent, he should have forewarned you. If it is because of limitations with the material, he should have forewarned you. But on the whole, no it is not acceptable. Repairs could alter what you have; losing the "polished finish" for example. Replacement, as has been mentioned, may be the best option.

I used polished carrara on my last bathroom remodel and it does, indeed, etch pretty badly. There's a polish powder you can buy online but I never used it. At any rate ... HONED ;)

FWIW, I have Calacatta marble basket weave tiles on my bathroom floor and shower floors. The grout is a soft gray and I have no issues with maintainance. It doesn't appear to be dirty and it just blends in with the rest of the tile. If after a number of years. I have had it installed for almost 3 years and it still looks the same as when it was installed. I love having small tiles as it makes me feel secure. I don't have need a rug or anything else to add visual clutter because the surface - even if it is wet or my feet are damp is so grippy. That is also true of the shower. I had larger tiles prior to my remodel and I felt I needed to be ultra cautious wherever I put my feet. At least for me the issues of grout maintenance and marble etching or discoloration or whatever were wildly overstated as - with normal maintenance and not fanatical maintenance - they still look great. If at some point a decade from now, they need to be restored, it is not that expensive to have a professional come in to clean the grout and marble. My building has it done periodically in the common areas and it always looks as good as new and those floors get significantly more wear than my bathrooms do.