What are the mail in and mail out address?

Mail delivery sent to wrong address!?? what would happen??? please help! 10 points!?

• So my friend she sent a mail which was suppose to be deliver to me unfortunately wasn't, she made a mistake and put in the wrong address. Would this mail get sent back to the office or will it just stay there??? also the address she put doesnt seem to exist. like for example.. the right one was 33B but she put in 13B whereas 13B doesnt exist. What would the mail carrier do? leave it as wrong address mails??? will it be sent back? and if i the reciever was to come to the post office myself will i be able to get the mail? or will i need proof or something since it was my friends fault for putting in the wrong address. PLEASE HELP ME! this is a really important mail that i need.

• Answer:

  if that address doesnt exist then the sender would receive a call from the post office that it doesnt exist and that she should come and collect it from there and send it again at the correct address!