l had the same with rifle that l bought from a auction which said they could provide postage, but when they came to send it the post office person said they could not seen it. l manage to get the post office number and spoke to the person who said they could not send it. and told them to look on their own web site which said that they can. but only by parcel force 48. l got my rifle posted, there are to many post office workers who take it on their own to say you can't post airguns.