Your parents could earn £40,000 a year and you'd still get £6,434. So your parents are clearly not earning minimum wage. Or at least were not last year. The only way it would fall down so far would be one of them losing their job. Only way they'd give you only £6,200 on close to minimum wage would be if you said you were going to live at home. You sure you know how much your parents earn?
Also, you currently live with your parents and they manage to support you too. So there's no reason why they couldn't spare £100 a month considering they probably spend more than that on you when you live away and they don't have to pay for your food and such.
If the income has changed by at least 15% then you can ask to use this year's income. Even in first year so call again and ask. You probably didn't make sense or the person on the phone wasn't trained fully when you first called.
Cheaper accommodation is available, you should've planned accordingly. And don't say there are no cheaper ones, anyone can look on the university website and check the hall prices and there are ones £1000 cheaper. So call and see if they could move you to a cheaper one.
You could even possibly find a shared house for less than £400 a month. If you can get out of the contract that you signed without knowing your budget.
Look at fast food places, warehouses and cleaner jobs. Don't be picky. Also try applying in person if you can. Some places like that will give you a job on the spot but will refuse you if you apply online.
People have had it worse but they planned accordingly. You can always take a gap year to work and save up money. Just because you take a year out doesn't mean you can't do uni and get a nice job after. There's no one else to blame but yourself for being in this situation. So I'm sorry but stop acting so entitled. Actually fallow the advice other people have given you and stop making excuses.