You don't list your province but the SoL on consumer debt is 2 years in Ontario. It use to be 6 years but that changed in on January 1 2004. Debt defaulted on in 2003 would have the old 6 year limitation but even if you defaulted on the last possible day it would have become stat barred 11 days ago.
I think this is just a scare tactic. No one calls to warn that they are going to serve you. What is the point of doing that? Giving people warning so they can hide assets and frustrate serving is hardly something someone who is actually going to sue you would do.
My guess is that the debt is stat barred and this is an attempt to get you to do something that will reset the clock. Be careful to not accidentally acknowledge the debt.

