In early December I received my annual drawdown from my ARF and I noticed that the amount was not correct. I contacted the company and they said they were sorry they had made an error ( treated it as an AMRF) and I would received another payment later in the month. I did receive the payment on 20th December but have noticed that the tax was not paid to Revenue until January and is in my 2020 tax. As a result of this my tax for 2019 is underpaid as the tax deducted from the ARF generally covers my liability for the year. Can I do anything to rectify this or do I just file my return as usual in October. We are self assessed.