Unable to cancel a contract at it's expiration date.

With my contract coming to an end, I've been unable to cancel it before it auto renews. The store has given me a contact number that no one answers, and after 11 calls to the contact centre and being put on hold for around 10 minutes each time, I get moved around until the inevitable call drops. The 2 times I reached a person, the line was so bad that they hung up. It seems as if the cancellation process is purposefully so complicated, that I suspect people get frustrated and just keeps the service our of exasperation. A call through to new sales/upgrades are, off course, answered immediately.