new tile an Grout

[Tom]

I put brand new tile in my Kitchen an Dining an hall an bathroom almost 500sq ft an then I used the added grout sealer instead of water an now alot of it is coming up,I used unsanded grout an when the spots were all over I got sanded an mixed it with sealer as well,I Have layed alot of Tile an never used the sealer an not water an now I wish i would have done the same cause of the problems of it keeps soft,I can take a knife an it will come up easy,some places are ok an others just dont seem to want to Hold grout,I had put all new plywood down an hardyboard over it so the tile would set ,can anyone tell me what to do thank you