I use the site only for teaching. 

Did you make sure that you contacted only the ones who want to learn Farsi or Turkish? Because I have sometimes people contacting me to help with English ( am  not native)  from an Arabic speaking background e.g...even if they can read on my profile that I learn only Korean at the moment...they are of no help to me as a language partner. 

The IELTS scores are 1-9. It's used to assess students for UK Universities. You need 5.5 for a Bachelor and 7 for a Masters in the UK. 4 - 4.5 is comparable to B1 level. 5.5 is B2 and 7 C1. I was also doing an IELTS course a few years back and what I thought is that everything had to be done very quickly. It's a time problem rather than an English problem. You need to process so much material in a short time. So you need to practice to skim loads of text quickly, just underlining the main words and being able to find the few points which answer the following questions quickly. It's kind of an academic skill, as they argue that students need to be able to read a lot in a short time, without understanding every word. In the listening I thought the difficulty was that they used many different accents, such as Scottish and Irish which are not that easy to understand, especially under time pressure.