FNB Mysteriously Lost My Money

Money has disappeared from my FNB account and I don't seem to be getting any assistance. I deposited money into my trading account on Sunday (24/11) using my card, then withdrew the same funds from my trading account into my FNB account on Monday 25/11 and it was received as a "reversal of goods purchased" yesterday 26/11. This morning I woke up to the same transaction debited again and no one at FNB seems to know where the money went as I did not process nor approve the recent transaction. I keep being told funds were reserved initially and only went through yesterday and that only one transaction shows but my in-contact says a different story. I was charged and on the 24th (funds reserved) and was charged again this morning for the same payment. I even made 2 purchases after 6pm yesterday and they both reflect the correct balance until this morning. I want my money back in my account. I want FNB to fix this or I'm seriously leaving this time around. I have had far too many unpleasant experiences with FNB.