Tamron Australia contact info:
Distributor for Australia is now Blonde Robot P/L
They appear to be based in Melbourne, but I don't know where.
What camera is the 70-200/2.8 mounted too? How long have you had it. Can you describe the issue with it?
.. and I'm backing up Am re the experience level too .. having 'a good amount of shot count' using various lenses, should be above beginner level.