I've got an overdrawn bank account in the US as l was recentely working over there (l live in Australia) and now that l wanna close the account l need to send them the money to make the balance $0 and to close the account.

They've given me a 9 digit ''ABA'' number and I am not too sure how to go about sending them funds.

Could l do it through a company like Western Union or do l need to go to my Australian bank to get them to send money?

Hope that all made sense.

l wont trust western union
l would go though your australian bank as they would know the correct
procedure (to wire the money and it will be faster)
if you go via Western union that means someone from the bank would
have to to a Western union office to get their money
plus western union might charge them a fee for pick up the money

you could do it with western union which would be quicker but cost more -=- take all he accounts to your Australian bank and they will make the transfer happen!!!