Classes on Skype


I have a question that I can’t find answers to on this forum nor in the terms of service.

It explicitly says in the ToS that that is not permitted to communicate with other users via Skype, however I see plenty of gigs offering lessons on Skype. Is this allowed? I just responded to a buyer request for a Skyped language class, but I don’t want to get in trouble for sharing contact information. What are the actual rules and how do I go about it without having problems?

Cheers and thanks!