Wrongly advised and now I have to pay for it

0n 29 September I called the 082111 number and enquired about my one contract, asking if the subscription for the BIS can be converted to a data bundle. the Agent as far as I know his name is Hendrik, informed me that this is posible. I made sure to ask him various times during the call if my montly account will stay the same (R209.50) . He confirmed this each time. I recieved 3 SMS's of which the last one stated \Your Vodacom GPRS Service has been migrated to 250MB Month-to-Month-TopUp". so everything seemed to be in order. Yesterday however I recieved my monthly email with all my account statements"