the pump module is internal and has to be removed from the tank. there is a gasket that seals the module and yes, it is connected to the work. if the light was not on before the repair, then it makes sense that they may have overlooked something on the repair.
if they wont recheck there work, go somewhere else and have it checked. if it is related, go back to midas and tell them and get re imbursed for the diag and tell them to repair it correstly.
We all make mistakes and when we do, we have to stand behind our work no matter what the cost.
Roy