Pyramid Healthcare

April 2020. I continue getting billing statements for invoices that I have already paid in 2018. I submitted proof of payment in January 2019 and still getting invoices for the same items. Latest I received is April 2020 saying I owe the same amounts that I previously provided receipt of payment for. Within the past month, I have called them at least 5 times and am told I will hear back from a "Supervisor" within 24 hours. Nobody ever calls and they continue sending the same invoices.