Paye underpayment

I owe revenue about 2300euro from 2009, due to an honest mistake I made. They sent me a letter earlier in the year saying
"I have coded the underpayment to your tax credits for 2011. This means your underpayment will be collected, by reducing your tax credits until the amount is paid in full."

I'm simply worried because, though I'm job hunting every single day, I'm afraid I won't have a job next year. I get 50euro a week from welfare, so I'm in no position to pay it back.

My question is, if I have no tax credits next year due to unemployment, what will happen?

Thanks =)

usually what the revenue will do is reduce your tax credits by a certain amount to claw back the amount you owe them. So if youre not working, they cant reduce your tax credits obviously. Give them a ring and ask them how much they intend to reduce your tax credits by and if youre not working how will they claw back the underpayment., theyre very helpful.

More than likely they will wait until you are working to start reducing your tax credits.

Thanks!
What exactly will it mean when they reduce my credits? Does that effect my wages?
I rang them today and the lady had no idea what she was talking about... Maybe I just got a new girl, I might ring them again or send a letter.
Thanks again