Our teachers currently do lessons through Skype, Google Hangouts, FaceTime, Zoom, WeChat and QQ. Not every teacher will have every method set up, but if your favorite communication method is not among the ones that the teacher has set up, you can always contact the teacher to see if you can arrange something.
When booking a lesson, you will get a page where you will see the communication method(s) that the teacher has set up. See image below.
Make sure that your method is selected and your id is correctly filled in.