Considering this "collection agency" was calling me about a debt from 1996 -- for which the limitation period has _long since_ expired, I'd say they're reproachable, at best.
In 2010, TD gave me a $240,000 mortgage, a personal CC ($5000), a business CC ($5000) AND $5000 overdraft on my business account WITH NO JOB. So don't tell me they're legit.
I sent them a registered letter requesting proof -- in writing -- of the debt, the original contract of the debt, their license number, proof that they are licensed to collect the debt, and proof that the limitation period has expired. I haven't heard from them since.
Statute of limitation on consumer debt incurred before 2002 is six (6) years; after 2002, it's two (2) years.
If they call you, do your due diligence, and make them prove they're authorized to call you.