Let the concrete CURE first. and dig your self to see how deep they are.
Sounds like the Hack Boys are at your house. Is it treated wood ,
many fasteners dont last with the new treated, ck the whole job out. Did
they buy bag concrete look at the receipt for how much. Did they buy
sand to dilute it ? I know of contractors that cheat every chance they
get, some take 50% down do 5% and you are the looser. Dont pay ill you
know its good