I'm guessing this is a grey market product...which Avaya will not support.
One option would be to contact a local Avaya business partner to get the system "legaled up". Since the product was probably sold second hand, it is offically unlicensed...and in order to get Avaya to support the unit you'll need to get it certified (i.e. pay for whatever functionality you're using).
Now if being offical & legal doesn't matter much to your company then here's what I would try:
Now my first order of business would be to do a google search for the default passwords.
After trying that route, then I would try contacting alternate vendors who support Avaya products but are not affiliated with Avaya. One example would be Walt Medak Associates in Portland, OR (
www.wma.com)