********** Transaction on my debit card

I made an online purchase on the 2nd of Nov'18 to the value of USD2.95 (R42.40), but when it went through my bank they took R1543.19. It is obviously way more and a ********** transaction. I immediately went to the branch at The Grove while the transaction was still Unprocessed. Case Number # ********** 1. They informed me that they can not stop the transaction, as I must bring them proof that I tried to contact the Merchandiser. I could only do this by Monday. Then the transaction was no longer Unprocessed, but Processed and off my bank account. I tried to contact the Merchandiser, but when I log onto the website and try to contact them or track my parcel, the pages are not accessible. And this is making me very nervous. I then e-mailed client services and got another Case Number # ********** 6. And would take another 7 working days for them to look into this? Another 7 days? This is *****, and they are suppose to protect me from such transactions. It took them two days to respond to my first e-mail. Yet again, very bad services, for ClientCare? Then I decided to go to the branch again on Friday, the 9th of November. They refuse to help me, as they are waiting for Card Dispute Services to handle the query. Even after I took all the proof that I have been trying to contact the Merchandiser, as they requested?