I have never had this happen to me before so I don't know if I'm thinking straight!
I sold my phone to Carphone Warehouse for £150. It was a year old and in perfect working condition, having been in a protective case the whole time. Carphone Warehouse wanted me to post it to them and sent the appropriate packaging to send them to in. Once they received they reduced the offer to £15 as it was damaged. This felt really odd, like they were having me on so I said - no, please return it. Cue 6 weeks of constant chasing for them to return my phone to me. It's arrived today and it's been smashed, and there are scuffs in one corner of the phone as if it's been banged or dropped. It's not been damaged in transit as the packaging is in perfect condition and totally appropriate for the phone.
I am furious as now this phone is totally unsellable. And even if it wasn't smashed up it wouldn't be worth what it was six weeks ago since I sent them it. I've never experienced such poor service in my life, and I truly believe someone smashed the phone before they returned it to me.
I've no idea what to do now. My AIBU is this:
YABU - there is nothing you can do, accept what has happened and move on.
YANBU - you've been scammed and ripped off, and have a case to complain to a regulator.