8 months after my general contractors had laid out the new tile on the bathroom floor, I noticed one of my large format tiles starting to wobble. It got progressively worse so I removed it and discovered that the thinset had not been laid out with an even trowel field. It was literally 5 globs on each corner and the middle. 

It looks like the the same treatment applies to the rest of the floor. Handyman came in and helped re-set the one tile, but I constantly hear bending and bumping on the floor. Nightmare? Not sure if I should ask them to come back or sue if they don't? Does it ever make sense to apply globs of thinset or were they just inexperienced and or lazy?