This is a matter of contract law. Still, since this is a renwal and not a termination, there likely is not a window of time that would prohibit your cancellation. Put it in writing and demand a refund before the service is to begin. You do not mention why you wish to terminate, but if it's a service issue, then maybe your termination will prompt their improvement in service if the contract does not allow you to cancel the renewal at this point.
Another protection would be if you charged the service on your credit card. You could dispute it if they do not allow the cancellation, but, again, it's a matter of contract.
Answered on Mar 12th, 2012 at 7:48 PM