Virgin Active Contract CANCELATION STRUGGLE

I have been trying to CANCEL my membership. Calling the call centre is a nightmare because waiting times are around 1 hour. I have tried different times a day and end up hanging up after running out of airtime. I tried the Twitter site and they only respond to questions not related to cancellations. Surely there should be another way besides the call center to cancel membership. The App doesn't give this option. Please cancel my membership?