Not a honest trooper

The day I registered with them I had to pay seperate for my simcard but the transaction wouldn't go threw then received a phone call from there accounts guy to say that the transaction could not go threw because I must lift my spending limit and then the accounts guy said make it 250 rand spending limit so I did every month I pay 250 for off peak 19 hours every month uncapped with topup options after a couple of days I saw the invoice it is at 942.35 cents and I didn't use there topup services at all can you assist me in this matter I feel as an client that rain don't give the client like me Liaan enough freedom to enjoy these services too the fullest that they provide rather they make there own chooses without the clients concent