Mtn
Overcharge on uncapped lite

I have a MTN uncapped lite account but have been overcharged for a thing called '' content charge'' for the past 4 months. I have not subscribed to any service as it is a wifi router and is impossible to reply to any subscription service request because obviously a wifi router has no screen or keypad. I would like to have my money back as it amounts to almost R500 extra than stated in the contract signed between myself and MTN. I cannot be charged for things I have not approved.
Thank you in advance