Welcome to PBF Axen,
I have had the same experience with my water table pond except I have hired guys 3 times instead of two!. I have the 4th guy scheduled for May. From what I have seen, the equipment used to date is just too small to have the reach required to get the depth in a water table pond. My 4th try, I have hired a guy with a large excavator (10 yd bucket) to get er dun! Yes, I will have to pay $500 to $1000 for road permits for transporting this big of equipment and it will not be cheap by the hour to operate. But at least it will get done the way I want it. A piece of equipment this size can make a huge deep puddle in two days.
I am not a pro, hopefully, one will see yer post and offer an opinion to your problem.
You'll never know what ya can catch unless you wet a line!