I'm looking to receive calls / send messages via a Windows PC for a radio station.

Traditionally I know Skype is ideal for this, however we also want to make some calls to mobiles and they charge 30c a min. Also Skype doesn't seem to be too popular for users to have and I'm looking at getting more calls in than making them.

WhatsApp's Windows app doesn't offer much, needs to be constantly married to a smartphone nor doesn't it accept calls. I've tried an emulator but that's not proving stable and we have to do something called virtual audio cabling to get the caller on the air, which I don't think can be achieved.

Anyone aware of a better solution that may be available?