Just heard a beep after answering, then it disconnected.  No idea who, what, or why.

This is a fraud campaign currently active in Canada using a series of Iristel VOIP numbers.  The objective is to obtain your credit card number and drain your account.

If you attempt to "opt out" your number will be confirmed as live and added to a suckers list for repeated future calls.

I didn't answer the call. Glad I didn't.