This increase is well documented, both in your contract and every bill you have received.
You can’t simply cancel this contract and immediately start a new contract as a new customer.
Your only option is to cancel this current contract, giving 30 days notice, or to negotiate a reduced price in return for a new minimum period with Virgin Media but you will not get anything close to the same services for as little as £79.
I suggest, given you are unlikely to get an installation from a new supplier at the moment, that you take the latter option unless you can manage without a phone line and broadband and accept Freeview as your TV option.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks