CellC changes Contract without Client Concent

I had two a contract with CellC for over 24 months. This weekend I was informed that both contracts were amended by CellC without my consent. Every month I paid for 100 minutes, 100 sms's and 1GB data. Now my package was changed to 100MB data. Why? How can CellC just amend a contract without discussing it with the client? Poor customer service.<br> I have just canceled by Data contract with CellC. Definitely considering of porting these to voice contracts to another SP.