I'm sorry to hear that you've had trouble with this Ardavan, despite your efforts to help people with their notebook entries.
Here is what I believe the problem to be: you're learning a language that is in very high demand, and the language you can teach - Persian - is not studied by many people, unfortunately, even though it is beautiful. Therefore, it's probably going to take you longer to find someone who will exchange with you because you have to find someone who wants to learn what you can share with them.
Many language exchanges, under the best of circumstances, don't work. Why? Because it's hard to find people who are willing to make a commitment, be reliable, and be consistent. All I can say is try to be patient and wait for the right person.