You'd need to raise a formal complaint. You might get a few quid back roughly equivalent of your charges per day, but VM explicitly deny liability for consequential losses as part of their business contracts, so any loss of business element of the complaint will be rejected. Your options then are to escalate the matter to the industry complaints adjudicator CISAS (if your business has no more than ten employees), if you've got more than ten employees then you need to consider consulting a lawyer as CISAS can't consider your complaint.
If going to CISAS, you'll need to be clear on the legal basis of your claim, since CISAS will uphold the company refusal to pay unless you can show some Ofcom regulation that makes VM liable, or that VM have broken some statute law.
If I'm honest, I regret you're probably on a hiding to nothing. The best recommendation for businesses who are reliant on either broadband or phone is to have a backup plan for loss of connection, but I appreciate that's no help to you now.
