I am in the same boat. Been with BT ages and always had a BT TV box thing, almost 100% certain I've had it pre Dec 2019. I cancelled BT Sport in September 2022 and received the request/envelope to return the box.
I opened up a chat session and they confirmed I did not have to return it and I won't be charged.
(I fully expect to be charged but at least I have a transcript of the chat session when inevitably I have to request the charge back!)
Sorry to ask the same question but I'm having the same problem. I have just stopped my bt TV but have had the box since 2016, but have been asked to return it. Might a moderator be able to help? @NeilO
I found it was worth ringing BT billing. Following my earlier post, I had a billing issue whereby after I had cancelled the BT TV package, I was still being charged for it some 2 months later. I rang them and got that issue sorted.
The agent then mentioned about the return of the box. I said how long I'd had it and that it should be considered to be mine, not loaned by BT. She agreed and noted the system accordingly. Within a few minutes of the call ending I received an email stating that BT had received my equipment back. Obviously they hadn't, but the agent had done what she needed to do to close the matter.
This way I have evidence that I need should it ever come to that.
I have contacted BT in the account and billing section via the online chat.
I have now been told I can keep my YouView box and it is now mine. I do not have to return it.
Many thanks to all for the advice and assistance.