Anyone else having/had their mail redirected repeatedly to an ex partner they have never lived with?

[Poddingtonpea4]

This occurred last year before Christmas when my ex moved address and recently when he moved again.
It seems linked to the tax credit department//other government departments..
I have never lived with this man or made any benefit claim ect with him so it is very puzzling. Our only link is that we have a daughter together.
The hm customs and revenue sorted it last time but couldn't say which department had made the change only that it was linked to my national insurance number. They have not yet replied to my latest letter about the issue (sent a month ago)
My ex has previously caused harassment problems and is currently withholding my mail.
I would really like to know if anyone else has had issues like this?

get on the phone to the revenue and demand action. As for your ex with-holding your mail, he's not allowed to do that but why is your post still going to his address?

Its a mystery how my mail has ever been confused with/sent to him as we have never lived together or made a joint application on anything.
Revenue rang yesterday and told me it wasn't their problem it was my local council that was changing the details. I rang the council and they say there is a new address associated with my NI number but can't tell me why and recommended I ring the department of work and pensions (which I did last year but they passed me to child benefit office). Neither department can assure me it won't happen again and refuse to speculate wether my sons NI number has been delivered to the wrong address.
Feel like I'm stuck in a big game of pass the buck.
About to ring DWP again, wish me luck!

sounds like he maybe claiming benefits for your DD.
i would write to very dwp dept stating that your DD lives with you and has always done so. Also your son. And that any claims he may have made to them may be fraudulent.
If you have never lived with him how is he holding onto your mail?
Check with royal mail that their has not been an application for redirection of mail! ( my ex did this) they will cancel it, also the children that live with you, because you are the primary carer he cannot redirect their mail either.

Make a claim of benefit fraud.

Has he tried to claim the CB?