FNB wont reverse online payment

Hi

On 12 Dec we had transaction go off twice on our account. The transaction Mannatech R600 was reported to FNB and they submitted for dispute via the callcenter. Later that week we went to FNB Langenhovenpark branch where they also submitted a dispute, but nothing happened. After that we were there 5x times and still the transaction wasn't reversed. Every time we request a reverse nothing happens