Worst service provider

They debited me R5000 and mostly R596 with no explanation I signed a prepaid contract for R139 for 20gig for 2 years n I cancelled when it expired but I still owe them money as their R5000 n R596 returned due to unexpected on the account this fees accumulated. Been with Telkom mobile for 6 years yet I have never got a call even my queries were never resolved or dealt. I left them due to network outage which was ongoing.