Ampath and their Service Provider Vericred bullying the patients

My son went for an angiogram in January 2018 - I did not receive an account and thus was not able to claim from my GAP cover and was not aware of any outstanding amount. I have not even received confirmation of his blood type as requested. In September 2019 I was approached by a company called Vericred to collect outstanding payments. The statement was send and I have on so many occasions send the proof of payment. Only in November 2019 was I advised that it was actually for a different account which I paid immediately, however now the amount was double as an admin fee and interest was charged. I refuse to pay these additional fee's as it was not my mistake and due to not receiving the account initially I was not able to claim from my GAP policy. I did pay the first account in full but are now harressed by this company appointed by Ampath. I receive monthly SMS's theatning to hand us over and phone calls with the phone being thrown down in my ear if I explain. This was raised with Ampath as well and all I received was an e-mail from Shaun Le Roux saying ''noted''. If Ampath send me the first account initially without handing it over to a subcontractor to do the work for them it would have been paid.