Well, for a modest amount of money, probably under $250, a private investigator can find the shark. The next question is, are you going to force him at gunpoint to dig up your yard, again without a permit, and do more "top quality" work? Your primary remedy against this guy is financial recovery thru legal means. But, just how much money do you think this charlatan has laying around? How much are you willing to invest to get a judgement which you can use to supplement your TP supply.