You're looking for something very specific. And it would make sense to invest in a tutor for something like this.

What I mean by 'specific' is that you're not after general English conversation, but training that'll help you crack the IELTS test.

I feel like I have to say that I mean no offence in advance but if you want something you always have to offer something, so 'Hey, I want to improve my *otherperson'snativelanguage and I am looking for some conversation practise", sounds like 'I want your knowledge and won't give you anything'.  Try to find out what you can offer. If you can't offer a language maybe you have some fun stories, know IT or Mathematics or anything. Also you write in this post 'I have been searching...', 'to improve my...', 'I desperately need...' '...you help me...'. I am not saying that you are self-centred or selfish but your writing style sounds like it. If you approach people on the internet like that they are likely to be repelled by it because it sounds like 'I will take and not give'. Furthermore, don't take a low request to response ratio personally as you are asking for the language that is most in demand. I get around 30 messages along the lines of 'Hi', 'How are you', 'I want to learn your language' and I really don't have the time to respond to everything. Rarely do I get messages like 'I can help you with *languagethatIamacutallylearning' which I like a lot more but still don't always find the time to respond to. A photo that shows you from the front (face!) would increase results too.

Kind regards and again no offence,

Phil =)