Looks like the contractor used up whatever he had left over from behind his garage.... ton of flaking, enough holes to fill to call it Swiss cheese. Fook, good luck....
The hot stuff adhesive we used in the boot camp might work for you Mike. It will dry crystal clear and would be the easiest fix. If you need to color the adhesive you will need to use the Superior GOLD. This video shows work on granite but it will work in you situation as well.