DH is self-employed and we over estimated what he earned in 2017-18 and got the wrong figure for 2016-17 (accountant confused us). I stopped tax credits in July as my mum said she would pay me the equivalent of the tax credits each month instead of having to deal with HMRC and the stress of trying to figure out self-employed income. Anyhoo, because I stopped the credits before the end of the tax year we have been hit with an overpayment (whole other thread).
My main question is, if we have been quite a lot underpaid will we ever get any of that back now that I have stopped claiming TC? Don't expect to but one can hope!!