Giulio Pagan

Hi I have received a penalty notice out of the blue for a missing tax declaration (tax year 2022-23). The UTR displayed is not mine and I find this quite stressful. I appealed and shared the records about my submission and associated payment. Despite that, the initial appeal was rejected and I will now have to ask HMRC to review the decision. I tried to talk to HMRC, but it is very hard to get through. HMRC is suggesting to pay the penalty but since the UTR is wrong, I am afraid I would simply lose £100. Any idea how this could happen and whether there is anything else I could do?