Has anyone else had problems with private halls student accommodation including those run by UNITE?

I'm having trouble with this "organisation" named UNITE, which specialises in private student halls of residence. To say this lot couldn't run a bath would be an understatement.

Here's a list so far:

1. Not having checked the keys were returned by previous tenants at the start of term, and making students in multiple person flats share keys, while previous tenants could still walk in and potentially steal their belongings. For several weeks into the autumn term.

2. Not inspecting and cleaning all flats prior to new tenants coming in.

3. Showing tenants into (and noticing the state of) smelly, filthy flats, with limited cleaning tools and telling them to clean it.

4. Not maintaining the flats, and letting them sit in disrepair.

5. Not processing direct debit forms, then instead of warning the tenants, sending them threatening invoices with red lettering.

6. Not being willing to budge over rent due, given the horrible service, even after having that explained to them.

7. Rudeness from other members of staff.

8. Not fixing the outdoor aerial for 3 weeks, so bad TV reception and no internet TV (which is included in our rent). And not giving a discount for that.

9. Not even giving you an inventory specific to your type of flat, leaving you confused over what things including furniture are actually supposed to be there, but are missing.

Does anyone have any advice on how to deal with these firms? They have you over a barrel, so if you withhold any rent, they heap late payment charges on you and threaten you with legal action, but if you pay up, you have no leverage with which to negotiate a reduction in your rent. They win either way, because you either end up in trouble, or end up paying the full price for some shocking service.

Have you had similar trouble, or even worse?

Are there any watchdogs or other organisations that can intervene on the tenants' behalf? I would like to hear from anyone who has successfully challenged a company like this.

What should I do? Please help! The bad guys shouldn't be able to win like this.