You'll need to threaten legal action to get anything done, I had to do the same with my letting agency, which is why I'm now looking at buying somewhere...

I had a window put through by vandals at about 3am on a Sunday morning, got an emergency glazier out to board it up (would have done it myself if I had any wood, nails, hammer, etc ), that cost me £145. Quick flick through my contract showed I had to get a crime-reference number from the police to pass to the letting agency, so I rang them Sunday morning to report it (didn't expect them to do anything, so wasn't disappointed when they didn't even send anyone out). Was called back a few hours later with the reference-number, so then waited until Monday morning for this gem of a conversation with the letting agency:

Me: Hi, I'm calling to report damage to the property by vandals early yesterday morning, a rock thrown through an upstairs window.
Them: Which one?
Me: Top of the stairs on the landing.
Them: Right.
Me: I've got the crime-reference number here, from reporting it to the police, and as per my contract, I'm also drafting out a written report of what happened, which you'll receive in the next day or two.
Them: Okay.
Me: When do you think you'll be able to get someone out to repair the window, then, and how do I go about claiming back the money paid to board up the window?
Them: Nothing to do with us, you pay for the boarding-up, and you organise and pay for the replacement window.

Cue 5 minutes of me stating exactly why that was wrong...

In the end, I called work and confirmed I wouldn't be in, and popped up the road to the Citizen's Advice Bureau with all the details. They had a look through my contract, and agreed with me that it wasn't my responsibility to organise or pay for the repairs, or the boarding-up, so they printed out a load of info, and I went home again and set to writing out a 3-page A4 official letter to the letting agency, quoting the various parts of my contract and various Tenancy Acts, to show exactly why it wasn't my responsibility.

In all this time, I'd left the window boarded up with the smashed glass on the outside...

A week or so after sending the letter, I got a call from them, saying they'd agree to pay both the refund for the glazier (I'd sent a photocopy of the invoice with the letter), and someone would contact me about replacing the window at their cost.

WIN!

Three weeks later, they put my rent up £45/month, but since I'm moving out soon, and it was a bloody expensive window, I won't be here long enough for them to claim the money back that way!