I must be naive but I don't understand, if they want the goods first then the answers no, I've sold stuff on gumtree but the bloke wanted to check it first so drove up from Devon. Paid cash, I chucked in something for free as he seemed an alright bloke.
Funny how i was 100% right this stunk of a scam and no you will hopefully understand why i was asking the OP for more details while also highlighting BT isnt unscammable