Irate at paying for things not requested

I habe recently upgraded to a Sony C3,i was told by Thapelo that i still have 4 months on my old contract and then this new one will activate. To my surprise i received recurring data bundles of 100mb and also sms bundles. After calling numerous times to have this removed i was told i dont have to worry it was a mistake on their part and my account would be credited. In good faith i left it there but when my bill went of on the 1st it was higher than usual hence my concern now. I tried their callcentre to no avail,even on their twitter feed no response. I feel that after many years as their client im not being looked after correctly. Im in need of an explanation as to how this data was activated . I buy my own airtime/data so how come i end up paying again? Could someone please contact me to sort out this mess otherwise im forced to go elsewhere with my businness in future. Also i spent so much money phoning that call centre for their mistake,you crippling a person!