Phones upgrade wrong billing as from November 2014

I was contacted in October to upgrade. Offered R 111.00 p/m on 2 contracts, no costs involved for upgrading when billed end of Nov I was charged R551.00 I.S.O R222.00. Enq started with no help then Lucrecia listened to the voice recording and promised to sort out accouts. Twice the service has been suspended on both phones the 1st time in March 2015 and then after a week Lucrecia promised that account has been sorted now the services were suspended again on 14 April 2015 I tried to call her on the phone and Bianca promised that she will call me back she was not available today I called again waiting for assistance from her side was on the phone for 30 min and again promised that she will call me back no assistance received. The service is really poor there is no solution, I want to cancel the contract not prepared to pay for the remaining months. To struggle for so many months with empty promises and such bad service is really unacceptable.