If you haven't accessed it within the last 150 days the mailbox has most likely been closed and all contents deleted. Not the answer you were hoping for, sorry.
Sorry about this but Graham_A is probably right. It's highly likely that your old email address has been removed from our systems.
I'll be happy to check for you though, just to be certain. Please respond to my PM (purple envelope icon, top right of page) and I'll see if we can offer any further help.