Cancelation of a Contract

I have been asked to pay for a service that I am not using. The contract that was signed was not explained properly. I sent a cancelation letter less than a month after signing the contract because I was being charged for a fee I did not agree to. But they take 2 months to reply to an e-mail. The service is pathetic. The cancelation was sent in March 19, started being threatened from June 19.