Claims approved for payment but claims are not being paid out

I am a provider. When my practice number changed the banking details remained the same. We sent the relevant documents multiple times. We have made multiple calls to momentum but they refuse to pay the claims we sent under the new practice number. They approved the claims but they do not pay us the money that they owe us. When we speak to the consultants all they tell me is that the money will be paid on the following friday which is the next payment run. Absolutely ridiculous. I jave claims as old as August that I am still waiting for payment for.