Cancellation of Fixed line

I moved at the end of February 2015 and duly notified the services provider to cancel the line as we moving. To date after numerous queries have been logged online & with their accounts division, i'm still being billed monthly for a service I don't utilize nor need. All I receive timorously is sms requesting payment & that the line will be cancelled. Haven't had any positive response from the service provider besides being threatened with legal action. The account should have been cancelled at the end of February, clearly if an account has been in default for 60 days services should be terminated, but you ****** monies from citizens with ************ business practices. produce evidence the line was utilized, and why im being billed. why hasn't the line been cancelled?