PIP overpayment due to DWP official error.

Hi , two months ago I was successful at Mandatory Reconsideration and my award was changed from standard on both to enhanced on both. I have a motability car and thankfully it was sorted out about one week before I was due to hand my car back so didn't lose my car at any time.
When I was given the revised decision I asked pip helpline if I needed to inform motability or anyone that I no longer had to hand car back. She said no and everything would just transfer over and dwp would let motability know. Haven't heard anything for dwp or motability since.
I got my first and thought it must have included back payments or something so didn't think anything of it. My second payment was the same, I didn't think this was right and that they'd given me too much so I called PIP helpline to query it. They said it was right but I asked if it was right when I had a car, which they then said no, I'm very sorry that's not right you have been overpaid. She apologised for their error, would inform benefits dept and they'd call me within 5 days. They haven't called so rang again today , was told no call back request had been put in but benefits dept were aware of and dealing with overpayment info.
Does anyone know where I can find info on what rights I have or don't have regarding recovery of overpayment when it occurred because of official error? Anyone had any experience of this and what happened? Can I be made to pay it back even though it was their error and I contacted them as soon as I thought it was wrong? Or any other information that could help me?
Thank you for any help given

Hi and Welcome to the forum, you might want to have a look at the following FAQ which explain where everything is

Welcome to Benefits and Work

I'm sorry you are going through this

I believe that the overpayment might not be repayable if it is proved to be DWP error. However, they certainly will not tell you this and will do everything they can to get you to pay!

I think your best bet would be to try and get some help from CAB or other benefits adviser (try doing an internet search for 'benefits advice' plus your town or postcode). In the meanwhile you could submit a 'subject access request' for the recording of your phone call (calls are usually recorded) if you can remember when you made it.

You might want to bookmark/favourite this on your web browser now so that you can find it easily in future. This will allow you to return with questions/comments without having to start a new topic each time. It helps us enormously when everything relating to the same claim is kept in one place - and I hope you will find it useful too