Iv worked in the financial world and these things where very common during our Chistmas parties and other piss ups. I have heard of people getting their money back so don't lose hope just yet. There was a famous case where a guy was charged over £20,000 at a strip club when he was off his face, he took them to court and won, his lawyer argued the fact if a girl was drunk and you offered her sex and she accepts but she's that wasted she didn't realise what she agreed to then the guy will be done for rape. So how can you charge money to drunk mans credit card knowing he's too drunk to say no.
Firstly you'll need to know what you've spent the money on, secondly was it using a debit or credit card. Any witnesses? Did you buy the service or was it offered to you whilst you was in a drunk state, if you willingly purchased it, then just give up now.
Without a witness, transaction knowledge/proof, you'll struggle. If it's a debit, you're pretty much fucked and I'd not bother. You'll have to take them to court to try recover anything and that just won't end well.
If it's a credit card, you'll have a slight and I mean slight more chance of recovering the cash ( thought it's still a low chance ). You are insurred on your credit for certain things, if you've been ripped off, conned ect you can make a complaint.
Sorry to bore you but I thought I'd post everything I know that may help.