Cancellation of AVG Subscription

Hello. I am desperately trying to cancel an annually recurring AVG subscription associated with a computer owned by my last employer. Originally and regretfully, I paid the initial subscription myself, and I no longer have the access credentials for my AVG account to cancel the subscription. All UK-centric support call numbers immediately disconnect. I have raised a support case number, and I’ve had no response. I’ve just been charged for another year. I no longer use or need AVG. Can anyone suggest how I can proceed, please. Thanks in advance.