The exact same thing happened to me two years ago.
They called me at work to say that I owed them money--in relation to a fee from Rogers. They told me it was 2 years over-due from an old address. I told them I had paid all of my Rogers bills early, and no knowledge of this fee. I also asked why 2 years has passed that they contact me now?
When I tried asking questions, I was repeatedly interrupted with "The payment is over due". So, worn out and fearful that their threats of wrecking my credit rating, I paid the fee they wanted.
I regret doing so now. Even after I paid when they kept hounding me, there is still an alert on my credit!!
If IQOR ever contacts me again, I will hang up the phone promptly. They should have contacted me in writing. Collecting over the telephone seems very shady.