VM don't have a customer facing email address.
If leaving you need to give 30 days notice. If you call today and give in your notice then your account will close at midnight on 18th March.
On most phone packages calls to the 0345 number are free for the first hour.
You can also call a freephone number 0800 052 0422, options 1,1, 4 and 4 (Thinking of leaving us) but best to call at 8am to avoid call queues
When speaking to that department you can negotiate a new price in exchange for a new contract or cancel.
You can also write to them to as per the terms and conditions. If writing send it by registered post.
Virgin Media Sales Operation Support, Diamond Plaza, Daleside Road, Nottingham, Nottinghamshire, NG2 3GG;
https://www.virginmedia.com/shop/the-legal-stuff/terms-and-conditions-for-fibre-optic-services#end
Dave
The Service you do for others is the rent you pay for your room here on Earth - Muhammad Ali