Breach of contract

I have a cellphone and wifi contract with Telkom. When I took out the contracts I confirmed with the sales agent that I want to pay a fixed amount per month . I do not want my account to vary. The sales agent had confirmed this. However, I have been receiving invoices for amounts which were not agreed upon. They have also downgraded my wifi contract from 20GB to 10GB.

A contract is an agreement between two parties over a given period. Telkom has breached that contract. I have requested the sales calls and copies of my contract but have not received them as yet.

Due to their incompetence I have suffered a financial loss. I have been ****** and violated.

Could the consumer protection act assist me or should I take legal action?