@Jacquelyn17
I left an item once and it took my host 3 months to finally send it back to me.
At the end of the day, you left it there so the host has no actual responsibility to actually send it on. It is purely down to a host's good will.
I do know of hosts who have sent items back and never received the postage cost promised.
Some hosts as such no longer offer to send anything.
There is nothing in any procedure or rule that states a host MUST return any left items, back to a guest.
Technically the host can ask you to return and pick it up.
Have you offered to pay postage and any insurance (if required). I guess so.
If it is almost a year one wonders if the host still has the item,to send back.
The only other thing is to have someone else pick it up from the host and have them post it to you (if the host has it still) ..like a courier or postal company who will box and ship it for you. Get them to do the work instead of the host.
Airbnb cannot get "aggressive" as technically the host has done nothing wrong. They have merely been slow on their decision that they have given you.They do not however HAVE to send left items back to guests.
If you feel the host has stolen them and committed an offence then you have to go through the Police and report it as a theft. Airbnb will look at it as something between you and the host.(That is what they told me when i left something behind and the guy took so long). Airbnb had little interest in doing anything to the account of the host I was dealing with.
Unfortunately hosts at times have things broken and guests do not replace those items and the host has to replace them.
One this occasion the guest has lost something and it may be that you have to replace it
As disappointing as that maybe
..(sorry if I am not giving you an answer you might have wanted)