Popping up of tiles Spread to more areas during attempt to hack off

[Justalvin 0]

First I found some 6 to 7 pieces of half body porcelain tiles slightly bulging in my living room 2 months ago. A knock on these tiles revealed hollowness underneath them, confirming they were popping up.

A contractor who was doing tiling job a few doors down the street offered to replace them with high confidence for a fee. They assured me that with proper cutting along the grouting between the good and the bad tiles, a good separation shld isolate the spread. 

When they started hacking off those problematic tiles, they however could not contain the spread to the adjacent row of tiles that were otherwise good prior to hacking. Now at least 3 fresh adjoining rows of tiles show evidence of popping up!  They quickly put the blame on the type and quality of the tiles which show evidence of warpage on those removed as well as poor quality of cement used!

The tile supplier denied it’s a tile quality issue and instead shifted the blame to insufficient gap between tiles and even the marble gum used during the previous installation. My grout is standard 2mm and the tile is 600x600mm.

 I agreed to the contractor’s subsequent suggestion and quote to replace the whole living room of about 700 sqft but just a few days ago, he decided to back out with irrational excuses. 

I am now left in the lurch with 3 rows of tiles removed revealing bare concrete flooring and another 3 rows of slightly bulging tiles.

With so many reasons cited by different parties behind the popping up phenomenon, I am now at loss as to what precautions I shld take in tile replacement to avoid recurrence of popping up!
 

I have quite a bit of carpentry sitting on the living room floor, so it will be a huge challenge to hack off the old flooring and lay the new ones at the same level as the old. 
 

Has anyone had any similar experience to share and any skilful tiler to recommend?