I have this problem with the university

So a bit of background I’m currently a study exchange student that has already finished their study program in Tokyo for 1 semester. I came here on the 24th of September 2022 and the visa that I got is applicable for 1 year. The study period ended on the 10th of February 2023. This program is through my home university’s offer not from the government scholarship program.

So here’s the problem that I’m currently facing and I want to hear your guys’ suggestions, The university wants me out of the dorm and back to my country by the 28th of February 2023 which was ok but they lied because the acceptance letter that I got from the university stated that I’m their student until the 31st of March and I also received a letter of residency for the dorm stating that I could stay until the 31st of March but in reality, they kicked us all out on the 28th of February. So in the beginning I set my expectations that I’m gonna return to my country somewhere at the end of March or the start of April.

I decided to plan my trip back to my country for the 12th of March because I was waiting for my PC to be repaired and also to do a little bit of sightseeing before going back, I already booked the tickets back too. The problem is that this university keeps harassing me telling me that I should return back to my country ASAP. Now they are threatening to report me to MEXT and immigration because I haven’t left Japan yet.

I tried to change my visa into a tourist visa but for some reason, immigration won’t let me but I told them the whole situation and they said that it’s ok if I leave on the 12th of March because I already have my flight tickets booked.

I have asked all of the other students who are planning to stay for a couple of days before leaving Japan and they all have a different approach to the situation. One guy decided to just change into a tourist visa but got declined, instead, he filled out a form stating that he was no longer a student from this university and immigration said that was enough and he could stay until the 21st of March. Another person managed to make the Japanese university apologize to her and let her stay until the 10th because her home university complained that they were mishandling the whole situation.

I’m very tired right now and I’m unsure of what to do so I really need any help I can get.