Differences between what is negotiated and what is put on VM's systems are common, and although the law is firmly on the customer's side, unless they spot it and act to preserve the evidence, AND are prepared to haul the company to Ombudsman Services if need be, then the company get away with.
Is it deliberate? Not actively at management level, but the company put so much value on new sales and retentions that poor sales behaviour is known and tolerated, and has been for many years, so differences between what was agreed and what's on system is Normal For Virgin Media. Field sales can be even worse than the telephone agents for mis-selling or outright lying, that too seems to be NFVM. There's also many complaints about sales practices that involve VM selling O2 contracts as a bundle.
Should Ofcom investigate? You bet. But they probably won't. VM have regularly breached Ofcom's General Conditions (in other industries these would be licence conditions, in telecoms it's assumed that anybody if fit to offer services, and then Ofcom hope they comply with the conditions), VM are always bouncing around the bottom end Ofcom's quarterly Hall of Shame, yet Ofcom publish that and sit on their hands year after year, doing nothing.
Individually, informed, active customers can enforce their rights. Others, including the vulnerable will just get crushed under VM's poor behaviours and poor customer service. So long as sufficient people renew with VM, then there's no reason why the company will change. VM's bad-hair CEO is one of the highest paid executives in the UK, at £8.8m in 2021 - he thinks he leads a successful company with great service and a respected brand. With a pre-tax salary of over £170,000 a week, do you think he feels any need for change? Even if the company had an epiphany and suddenly decided it wanted to change, the problem is endemic and cultural - that would take a real leader (of which VM have none) around seven years of hard work, the replacement of most senior managers, the change of all performance incentives, new objectives, and monitoring systems. This is not going to happen.
And that's why I'm now with a small ISP (Aquiss) who put customer service as one of their key priorities. Other options for those who conclude they want a company that care include AAISP, CIX, IDNet, and uno. They don't play the large ISP game of massive discounts for 18 months and swingeing in-contract price rises, so will appear more expensive, and their offer may be differently structured to large ISPs' so check what you get. But there's a price to customer service, you pay it or you don't.