they can't even protect us about overcharges on client accounts, what about overseeing that they are providing a decent service to those rented networks?

not to mention the good old lowering of their price until they've killed competition, again.

They do police overcharges and excess billing; both AT&T and Verizon have paid massive fines for this in the past decade.

The agency is not responsible for policing quality of service--that is a function left to the market. Nor does the agency simply get to decide that it will police quality of service--it must be granted that authority by Congress.