I had the same problem at first, but I overcame it. Firstly, when you contact someone who's new here, you should expect that they may never come again. So, it's better to contact people who have a lot of activities here (it's obvious that they're serious about learning and also willing to help). Secondly, you can't rely on messages here to talk with your partner, so exchange Skype IDs (or anything else) as soon as possible. Also, you're a native English speaker and almost everyone here wants to learn English, so it shouldn't be difficult to find one. But due to time differences, you should set a fixed time to chat at. And remember that don't need too many people to talk to, three or four people would be perfect. Hope this helps.