Cancellation of contracts

Have had a contract with data and free minutes however the sim card became inactive and all the data and minutes forfeited, then I tried to cancel a contract but the customer service agent constantly tried to sell me new products and a new contract, they just don't take no for an answer. Extremely frustrating! This is the second contract that I have tried to cancel with this happening, the first contract which was to be cancelled was not captured by the agent and I had to pay an extra month for services I didn't receive/use!