Unauthorized charges and magazines

I have an account with TFG total sports from this year. I was approved for a credit on f R4800 if not less. Everytime I buy something I made sure that I also pay and have always been paying paying. Around May I received a message from TFG stating that I owe R6600. I was shocked because I was approved of R4800, how did it reach R6600. Ever since I have been trying to get it sorted. I am a frustrated customer right now paying for magazines I know nothing about.

To my surprise in june