Retaking a course but the exams are exactly the same as last year's I recently faced a problem that is, I took a course at my university last year and got some grade for it, so for further improving it I gave the course this year again.

The course is purely evaluated based on oral exams on the take-home assignments that are handed out.

Coming back to the problem, I registered for the same course this year at my university, and apparently, the set of take-home exams are the same as the last year. Since, I know most of the correct answers, I just corrected the ones I made mistake on last year and submitted the improved set of the report this year.

However, it seems that the course instructor is not so happy about it  (and does not want to evaluate me) as I just re-did the same assignments by improving the previous one. 

Having said these, what I see as the problem is that in the course information they have not said anything that whoever is repeating the course should inform the teacher to get new sets. Also, I registered for the course with a new registration and not a mere re-sit. Since they have given the assignments the same, I don't agree with them saying that they are not happy with the report that I handed in.

So for avoiding the conflict of interest, however, I withdrew from the exams, also, I know that in an ethical background that is the right thing to do (technically I did not do anything wrong). 

Could you advise me who is right and wrong here and also please do advise me on the technical base, who is on the wrong side and what could I have done (I know that ethically this is wrong).
If a student is allowed to register for a class as a "new registration" as opposed to a resit and the student attends the class and does the work, the student deserves to be given a fair evaluation. While reusing assignments and examination materials is not optimal, it happens. Not wanting to (re-)evaluate a student on reused assignments seems reasonable. I would expect the instructor and department chair (or teaching chair) to work with you to resolve the issue. making you withdraw from the class seems to be an unreasonable solution.