@OonaghdExcuse me for butting in here, particularly as I'm reading between the lines of both the problem and the response, but the following may be worth giving thought to.
Forum staff: The deal your father was on previously, may not be on the system anymore. Which would be one reason as to why we have not changed it back, which I understand is an inconvenience. The only way we would be able to help from here, is if you could pass security on his account, is this something you are able to do? We can not promise the £49 he was on previously, but we can see what more we can do. We do not normally deal with package changes from this platform, but due to everything you have said, I am happy to help.
That's not a confidence inspiring response. A contract existed between the OP's father and VM. Due to VM's poor quality staff, the contract was cancelled, which regardless of VM's T&Cs, the company cannot do, any more than the customer can unilaterally change the deal on terms they'd like. The fact that VM may have wiped the original deal off the system is irrelevant, the company broke their contract, and are now obliged to:
1) Reinstate the original, discounted fixed term deal, on terms at least as good as the original, not some less favourable compromise.
2) Refund any payments taken above the agreed contract price
3) Pay compensation for wrongful disconnection
4) Pay additional compensation for setting up a new contract on unagreed terms
5) Pay further compensation for failing to sort this out promptly and effectively.
There's also a strong suggestion that the OP's father may be a vulnerable customer, which is a regular area of miserable yet unapologetic failure by Virgin Media. If both 3 and 4 are relevant above, then you're talking at about £150 for number 3, and £70 for numbers 4 & 5, but if your father is vulnerable through age, hearing loss or other cause, then you could double those. Maybe all of those things are what the staff are sorting out, but I don't get that impression, albeit they can't go into details in a public forum.
So, @Oonaghd there are formal routes to achieve all five of the above if VM won't sort this out quickly and generously. They involve formal complaint to VM (which you'll probably need to do in writing), this will likely be fobbed off because VM's complaint handling is done to the company's customary standards of everything. If it is fobbed off, you reject the "resolution" they offer and ask for a deadlock letter, and when you get that you approach CISAS, the industry complaints adjudicator. If things get as far as CISAS, make it clear if your father is vulnerable - this is very relevant to a complaint adjudication. If you need to approach CISAS, then I also suggest you do a short "drive by" complaint to the regulator Ofcom. Ofcom don't get involved in individual complaints, hence why you don't put too much effort into that one, but they do consider the company's performance overall.
If VM will sort out the contract price and duration, but won't generously resolve the compensation aspects to you and your father's complete satisfaction, you can use the formal route to get that paid.