Ampath and Vericred

Settled an account with Ampath in January 2018. The account was then sent to Vericred. Despite advising them of the account settlement for almost two years, I have been told I must pay them for their costs. I have confirmation from Ampath that the account has been settled and sent Vericred the proof that the account has been settled, yet I am continuously being hounded for payment. Absolutely poor service as neither Ampath or Vericred are prepared to LISTEN.