Affiliate Commissions From Calls?

There's an online shop thats related to my niche. They apparently have an affiliate program which caught my interest. I cant find a lot of information about the company. I just know that they sometimes put up ads on google.

They were very friendly in having me join their affiliate program even to the point of creating some custom buttons for my website.

I however notice that a customer can buy their products by calling them. When I ask if we get commissions from those too. They said yes, and they have a complex system that allows it to happen.

Now, I am not quite sure if thats possible or they are lying. If they are I might just look for a different source instead.