tax credits

hi, looking for help, we've received notice from revenue that we under payed our tax. it appears that when we got married I got married tax credits and my wife got single credits, as paye workers we did not notice this. p60's came and went (again took no notice as paye workers)only really interested in the bottom line and how to make ends meet. got a form from the revenue before christmas fill it out, not think to much about it(looking for last years p60 etc) now it turns out we owe them 11,000 going back to 2011, they have cut our tax credits down to 24 euro a week for the next 3 years. don't have good understanding of the tax system, any help appreciated, thanks

If you are married you are entitled to a tax credit of €3,300 between you.

So if your wife also received a single credit then you are underpaid by €1,650 per annum.

Do you have your P60s for the years, did you get a balancing statement from Revenue for each of the years.

Do you have any medical expenses that you can claim to reduce the liability?

gave in med 1 forms for last four years, will reduce it by about 200 euro,only got p21 paye balancing statements last week for 2011 under payment 2,269, 2012=1,589, 2013=1600, 2014=3,405 and p60's for last year gave in today but earnings about the same as last year so underpayment will be about 3,400? on panel 4(p21)tax credits states personal tax cr self-3,300 spouse- blank. paye tax credit self-1,650 spouse-1650 i am at a loss to understand?

Why is 2014 underpaid by that much?

If you want to Pm me the figures I can look at it tonight. There is something else wrong in 2014.