I wonder if this free course offered through edx.org might be helpful to you:

https://www.edx.org/es/course/english-grammar-style-uqx-write101x-5

It starts in just a few days.

I love edx.org courses.  The videos all have the transciptions, the speed can be adjusted, and they have many tools appropriate for language learning. 

I have been auditing several courses in Spanish-- it is so nice to learn things while you are working on the language.  Most of the courses are by very well respected universities.  If you do not care about receiving credit, the courses are free.  You can also take old courses that have been archived. 

There are several courses specifically related to improving your English, both in the sections related to languages and the section on communication. However, for improving listening, skills, reading skills, and vocabulary, there are many, many classes in English on different interesting subjects.   That is my preference.  I have not taken any of the courses designed for learning Spanish.  I have taken courses in Spanish on other topics. 

the coursera courses are great, mostly to improve writing and increase your active vocabulary you have to do a lot of reading and listening aswell, cause words that you know when you read them again and again in different scenarios you get a better understanding of them. 

Also on coursera.org or edx.org there are some IELTS courses.

Mostly you will get score in IELTS according to your skill level, and skills are gained overtime. However, you can get a point or so higher if you do thorough practice. Lot of material is available online.

Feel free to contact me for further advice, I have taken the test twice.

Adib,

Did you also see their course specifically for preparing for the IELTS? It covers listening, speaking, reading and writing.

https://www.edx.org/course/ielts-academic-test-preparation-uqx-ieltsx-1