Thanks for all the advise.. They have now stopped my tax credits.. And said to make a joint claim.. Do I still need to send all my bank statements and bills to concentrix.. Just don't know whet to do tbh.. x

Thank You Honeybee x

Hello... I am also in a similar situation, I have had a letter saying that another adult is living at the house and I make a single claim, I am just about to send all my stuff back they have requested. Can anyone HELP me on what to put in the letter. My ex is registered at the address as we have a joint mortgage and bank account, I have let him use the address, the ex lives with his parents but we still are good friends and he visits to see our daughter most days. I have also told HMRC that he as now moved back in to the spare room and they have cancelled my single claim and said I need to make a joint claim, but cant see why I would need to make a joint claim when not together. How can I prove that I am single when we still have joint bank and mortgage? He is a good Dad and person and we are friends for the sake of our daughter and I didn't want to put her through what I went through when my parents split up..