Data expired because of call centre not willing to assist

I received an sms from cell c, telling me my data is going to expire (3Gig). I must buy an extenda bundle. After following the steps they gave me didn't work, I phoned the call centre to tell me how I must buy the extenda bundle. After telling me I am not the account holder, they refused to just tell me how I must buy the extenda bundle and the call centre lady started screaming at me when I just tried to explain that she just needs to tell me how. Now I lost 3gig of data. This is pathetic. When this contract is finish next year July, I will cancel the contract for me and my husband, and try another service provider.