Differences in opinion when teaching a course jointly with another instructor I am working as a university lecturer in a local university in my country. I am sharing one course with another lecturer who has been teaching that course for approximately 3 years for now. A problem began when some of my students complained that they were not able to cope with the material. The dean was not willing to lose those students (as they pay a monthly tuition here); so he decided that myself and the other lecturer should switch groups.

Actually this situation has transformed in something worse. The other lecturer wants me to strictly follow the problems and solutions that he has on-line. I particularly do not agree with that situation mainly because I have a higher educational background, apart from research in my field of expertise.

I have written a complaint to the academic coordinator, explaining my situation. I feel the students here are treated like some kind of stocks in a bursary market. The university loses money if they leave. What would be a good thing to do?
There are some things which are unclear in your question. However, I'm going to make a few guesses and if any are wrong then you might want to disregard this answer altogether.

It sounds like you have more education but less teaching experience than the other instructor. If you are new to teaching, one very common issue that new teachers often overestimate students' abilities. If the other instructor has more teaching experience then you might be better off 'going with the flow' for this first semester.

Another reason to go with the flow is, as Chris Gregg pointed out in his comment above, students once given a syllabus should not have it changed on them mid-stream. It's bad enough (for them) to have to deal with a change in instructor, they should not also have the syllabus changed on them as well. Consider what you could learn from the way the other instructor designed the course - we can learn things from those with less education than us.

I don't know what you mean by treated like some kind of stocks in a bursary market but, of course, without students there is no point of teaching so, yes, they are important. Nobody wants a large group of students to leave.

So, my suggestion is to try one semester following the other teacher's guidance and next semester consider taking everything you know, and everything you learned, and improve things.