Chat vs call / offline vs / online

The application is very interesting to learn languages but there is some enhancement to do.
In fact, people are always online even when they are not available so it is very difficult to find somebody available to speak...
So I sent 3 message to the application team but they are not motivated to enhance this big issue ! Wasting time instead of talking quickly with someone available !
Please do something about that, like setup severals status : ready to talk, ready to chat, or offline... You can also add a filter to chose only people who want to speak !!!

Malik - Paris about Tandem: Conversation exchange, v1.5.3