Telephoning is the best method, it also allows you the option to negotiate for a new discounted deal
The call centres are open. You can call 150 from your Virgin landline, or 0345 454 1111, Options 1,1,4 and 4 (thinking of leaving us) but best to call at 8am to avoid call queues
You could also try the text messaging service. Just send a text with a description of cancellation to 07533 051809. Your message will go into a queue and a representative will respond to you as soon as possible. It may take a few days.
Or write to them to as per the terms and conditions. If writing send it by registered post.