Appalling customer service

I have requested a cancellation of my domain hosting package, wanting to transfer to another service provider. My account has subsequently been suspended due to an 'unpaid invoice' which is an annual invoice that I refuse to pay, as I have used the service for a mere 11 days this year (and having read reviews of delays in refunds by this company, I am even more reluctant to pay it) . I have sent numerous support tickets, requested a pro rata invoice for the month of January, and requested that someone calls me. None of my calls to the call centre (whether to the support or the billing department) gets answered. I am put on hold for 15 minutes or more without any indication of how long it will take for a call to be answered, if at all.