********** Transactions "Advance Cash Transer"

I've got an credit account with Game store for more than four years now. I've just found out from Clearscore websit that I am owing them about R15000 that I completely don't know of. I decided to go to their Westgate branch to find more information about this matter. I found out that someone has **********ly made two transactions which they call "Advance Cash Transfer " of R9720 and R5227 consecutively. I don't even know what is this "Advance Cash Transfer" and I don't know how and when it happened because my Game card and ID has alway been with me. I have opened a ***** case and submitted the all the relevant documents but I don't know how long it will take them to resolve this issue. I will close my account as soon as they resolve it because their customer security system does not make me feel safe.