Pathcare double charging

I did a covid test with Pathcare on 20 October 2020 and as usual you need to pay for it before they do the test. I made the payment with my Cheque card (as they do not accept cash) and the sister took the proof of payment and stapled it to my test papers. Now on the 26th October 2020, Pathcare sent me an invoice to pay for the test that I did on the 20th of October 2020 and already paid for. The money was deducted from my account and I have proof of the payment. I phoned them but they came up with an excuse that they can't find the payment that I made. To me this is ********** to try and double charge a person for a service. People please be careful for Pathcare double charging their clients.