OK, I can see English is not your first language, so I'll try and keep this clear, but appreciate that my advice below is complicated. I (or other forum members) will try and explain any points that are not clear.
Is your current £59 contract a fixed term contract? These are normally the discounted 18 month deals offered to new customers, but with expensive early exit fees. If you are in this type of fixed term contract, and it has not been changed, then your best hope is that you qualify for VM's Essential Broadband - the main criteria is getting Universal Credit. Be aware that Essential Broadband is a very, very slow speed and you'd have to really be desperate to take this up.
If you are still in any original fixed term contract (not a new fixed term contract), and do not qualify for Essential Broadband, but cannot afford the current arrangements, then you can try calling Citizens Advice who may be able to offer good advice on how to manage if you can't afford the bills. They may recommend you discuss payment difficulties with Virgin Media customer services again, and telling the agent that you cannot afford the bill, and you need to speak to somebody about a payment plan. I can't say if VM will help but it may be worth a try - some companies are very good with payment difficulties, some are very poor.
If you are in a fixed term contract, and you simply stop paying the bill, then your connection will be terminated by Virgin Media, they will add late payment charges to the closing balance of your account, report you as a bad credit risk to credit reference agencies, and pass the debt to a debt collection agency. A payment default on your credit history could be visible to potential future employers or landlords, as well as making it more difficult with future phone contracts, energy, or anything involving loans or credit. These are all very bad things that you should avoid at all costs if you want to have a future in the UK.
If the agent has started a new contract despite you not agreeing to that, then the company have broken UK law, and that actually puts you in the strongest position to get things resolved to your satisfaction. That's a very serious issue, and the company will have to undo the new contract, and pay you compensation for putting you into a new contract without permission - I'd suggest that at least £150 in compensation is due (forum staff, you know the drill). If this is the case, you should insist that by negating the old contract without permission, and imposing a new contract without permission, VM have broken the terms of the original contract and that they cannot now reinstate the terms of the original fixed term, and that the settlement needs to be compensation and that the new and old contracts are cancelled and you leave VM without paying anything extra. There are good legal grounds for this, although it might involve formal complaints and adjudication, which costs nothing, but would take a couple of months during which you'd still have to pay the bills. If needed we can explain all of this process for you.
If you are not in a fixed term contract, then cancelling the Virgin Media contract and paying all outstanding bills may be the simplest thing to do (although the company intentionally make that simple task difficult).
And finally, if you're struggling with broadband bills, chances are you're struggling with other bills. Don't let the weight of all these problems get you down. Deal with each bill or outgoing slowly, logically and methodically, speak to Citizens Advice, think about what steps you can take - eg any outgoings that are voluntary and can be curtailed, such as streaming subscriptions.
