Vodacom
Over charged on a top up contract

I logged a call S3-TS22p-PT9EP on the 10th and no one is coming back 2 me with my query. When I follow up then get bad attitude consultants who tell me that my issue is being dealt with so I should lear to be patient. I have an agreement with voda that my montly cost is R589 but 2 my surprise I'm billed R880.I'm frustrated coz I'm not getting the answers. I will take the matter forward coz I know my consumer rights