SIM CARD NOT RECIEVING DATA/BROWSING THE INTERNET

My cellphone cannot recieve data/browse internet when using my CELL C contracted sim card ***. It can recieve data and browse internet when using any cell c, vodacom, mtn sim card. I phoned their technical center but couldn't get help. They sent me Network Instructions for my phone and I did all that but still no resolve. I did a sim swap but it's still not working. They called the BlackBerry technical assistant and he said the phone was fine but the problem is with the sim card. I can phone, sms, mms, whatsup on the sim card but cannot browse the internet. <br> <br> This has being going on for a month with no help from CELL C. I was advised to do a second sim swap but I know this will not help. I want a permanent resolution from CELL C. I am paying R389-00 every month and recieve 1GIG of data but now I can't use it. The reson I activated this contract was for the data I get every month. This contract is useless to me if I can't use data. Maybe I should have my contrcat cancelled and demand my money back for the gigabytes I didn't use for a month and a half.