Stratum using delaying tactics

I work for a Doctor's rooms and in the last 6 months the majority of our patients who are with Stratum have experienced problems receiving payouts. They are told by Stratum that their condition was a PMB, even when it was pre-booked and the patient was aware that we are not a designated provider. In my opinion this is merely a ploy to delay payment. Stratum need to start being more transparent and honouring agreements.