Poor service

Am so disappointed by old mutual money account, money was taken out of my account ,unauthorised, i went to the nearest o/m, when i get there they connected me to someone on the phone who said that is not a debit but online purchase of R399.20 and R239.20, they cant refund, and i tried to tell them i did not purchase any thing , they said they dnt have option but to replace the card n i must open ***** case....i mean, still that card replacement i must pay for it , how am i assisted as a client ? I did not buy anything online ,how do i convince them to pay my money back. Ts even worse cause on the app you cannt reverse any unauthorised debit Frustration is an understatement Am so dissappointed