Hi, first time using this site, not sure if I have posted in the wrong section, couldn't find another which was more appropriate. I received a letter from HMRC today, was a bit confused as to what it meant exactly, so I tried to ring them to find out, but there's an automated voice message saying that due to industrial action today, my call cannot be taken - wasn't the strike on 30th Nov? The letter either means I'm due a refund or that I owe them over £1000 - I'm a stay at home mum and can't afford to pay it back! It goes back to 2006/07 and 2007/08 tax years when I was working. Has anyone else had problems speaking to them; I've tried the tax credits and child benefit lines and they are all the same?