Preauthorised procedure messed up by momentum

I authorized venofer infusions in February. The dates for the authorisation were messed up, but luckily I realised this and called to correct it. I was assured that all was correct. I went for the 4 infusions and then get a msg from the doctor that the venofer meds was not paid for. How can the infusion be done without the venofer? I called momentum and was told that it was not paid because the dates were incorrect. How is this possible when I called to correct it. The account was resubmitted by the agent and now I get a msg (for one date) instead of the 3 dates queried saying that this has to be submitted in real time. Please can momentum just sort out correct payment for something that was preauthorised?