I have to guess here as I haven’t seen (and can’t) what you wrote to avast and what they answered, but that answer sounds really strange to me.
Perhaps they didn’t understood you problem/question correctly.

It doesn’t matter where someone is living.
Support is there for everyone.

As for the trial, I would simply download a trial from the website and use that.
Ofcourse remove the current installed version completely first as well as remnants from other pre(vious) installed av’s.