Conniving TFG splits purchases to rob clients & then ignores them

I made an online purchase on 04.04.2018 for the total amount of R1937.25. When I received my account I noticed my balance was a bit high and all the items from the purchase were split. I then added up all the amounts and see that I was charged more than R500 more than my purchase. I have been trying to sort this out since then. I have emailed multiple times and the only response I get is that TFG are so backwards that they can not assist with email queries even though you advertise the email address. When I phone in i just get sent around in circles. How am I supposed to sort this out and how do I make sure you don't rob me again????