Complaint to university

The post has been checked and if you are challenging my English ability please go to language course area

Thereby proving @Stiffy Byng's point. *chef's kiss*

What was the outcome of the OIA review?

I applied complaint twice to OIA. First time they asked me wait for university reply
One year later, I complained to OIA again as the university has never ever replied me. OIA said it has been too long they don't want to accept the case
Now I have to go back to university to chase the reply..

Then you still need to follow the formal process at the uni and chase them up if they fall outside of their own timescales. When you have a final outcome, then you go to the OIA if needs be.

I appeal my case first and the professor who in charged the case refused to accept the appeal as it was out of the timline. Then I applied the complaint but they have never replied me and the complaint procedure clearly said it is different from appeal. I am not sure if they will accept my complaint as different people have different opinions
Initially my case was in charge by mental health team, nobody figured out they didn't follow the formal procedure. I complaint it several times they just ignored it. People even said I don't respect professional at that time being

In most cases you would complain directly to the relevant department, and then if you were not satisfied with the outcome you would follow the wider university complaints process.
The wider uni process should have specified timescales to give you a formal decision. That’s the bit you need before raising again with the OIA.

People might help you if you would explain in an intelligible form what your concern is. Your opening post is unintelligible. Your later posts indicate that you have a complaint arising from something said or done during the pandemic, but it remains unclear what your complaint is. Your written English is hard to understand. Perhaps English is not your first language, although I would assume that you would need reasonable proficiency in English in order to study at Durham.

You are still not making yourself clear. Do you wish to complain about the university, one or more members of staff at the university, or one or more students of the university? Is your complaint about an academic matter such as a grade, or about the conduct of one or more individuals?
You indicate that you have already taken steps in some internal university procedures, and have also been in contact with the OIA. But without a clear narrative of what you are seeking to do, and clear information as to which steps you have already taken and the relevant time line, it is difficult for anyone to offer you meaningful assistance. It is not clear what objective you wish to attain. Maybe you could set out your concerns in your mother language and run the text through Googler translate.
It may be that you have already exhausted all avenues of complaint within the university and externally. If you have not obtained what you regard as a satisfactory outcome, that does not mean that you can keep on raising the complaint either internally or externally. Disagreeing with a decision is not ordinarily in itself a basis for challenge. As for a further challenge by way of, for example, legal proceedings, the Courts are generally unwilling to intervene in matters of academic judgment or the internal regulation of a university, save in quite limited circumstances.