Heerschop Pienaar Xaba Inc underhanded tactics

Heerschop Pienaar Xaba Inc is a firm that handles payments on behalf of FNB. I paid my debt to FNB through this law firm. I unfortunately made a the payment twice. It has been 21days since the transactions were made. In the same day when the payments were made, I notified HPX Inc on the double payment and sent both proofs of payment. I was told that with in 7days I will be reimbursed. I wrote an email to Vinolia she didn't reply to the email. 3daus later, I called the firm to speak to Vinolia. Her reasoning was that she is sorry that she didn't tell me initially that I was to provide proof account so the matter could be resolved. I sent the proof account. The matter was not sorted. I then requested to speak to he manager, Pearl then **** to me 3times in one day over the phone. She said she would send me a email she didn't, she said she would call and she didn't. The third lie was she would copy me in an email and she didn't. I truly think that issue is not being handled and they have a big brother mentality. They are bullies and seem have an underhanded modus operandi. Please assist me with handling the bully law firm