They dont want to cancel my contract

I am really upset at Netstar, I have two weeks now after the call for a contract. Then after a week with no fitment, I decided to cancel the contract, I called their cancellation department, and they said its cancelled and i will get a letter. They didn't send the letter, I then called their customer service and i find that my account is still active, and now they make excuses that their system is down after their asked my ID, and now thy cant cancel...Can you please cancel that contract