Hi Omar, not exactly sure what the problem is other than you cannot change account details due to old number being in the frame or new number not connecting to the new account details?
I would think the best bet would be to email airbnb or ring them directly if you are able and tell them your predictment in putting a new account up.. I guess they will check out you are who you say you are by some means of identification and sort you out with what you need.
Good luck
mala