How many times must i call for urgent help?

Awful service. Made online purchase. Saw amount debited was R3000 more than it should have been. Sent secure message to cancel. Phoned 5 times each time being passed around. Told not processed yet so can cancel it out. Time it took for me to get assistance it was too late. Now i have to wait 5 to 7 days to see if my dispute will be successful. Really??? Appalling service.