So you returned in Fall(?) of 2022, and applied for graduation Spring 2023(?), at which point they wanted you to take 2 courses (probably to replace the 2 of 3 C/not passing courses from the first year that were not retaken). You did not do this, appealed to not have to take the courses, denied. January(?) 2024 you asked again to be able to complete your PhD, without having taken those 2 courses, and were dismissed March 2024.
My guess is that when they reviewed your file for graduation requirements, they saw that you did not have enough credits that met academic standards for grad students (B or higher?) They gave you a year or so to replace the C classes, saw that you hadn’t done it and had already appealed once, so at that point decided to dismiss for failure to meet academic standards. Allowing you the opportunity to make up the credits was probably already viewed as an accommodation due to the disruption caused by your advisor leaving and COVID. The second time you asked to NOT have to do what they had already told you was needed, they dismissed you.
If you really want to get that PhD, feel like you haven’t burned your bridges, and are willing/able to do what they asked (take the classes with no further financial assistance?), you could try talking with your advisor/trusted professor/dean and see if they would help you get a second chance (and then do exactly what they need from you for you to progress). It may already be too late for that, I don’t know. What exactly did they say in the dismissal letter?
If getting back to the PhD is not an option, is there any chance of getting another job that will sponsor you with your current credentials? How long do you have to get this taken care of?
I know someone on a work visa who was unexpectedly fired from their job when they got on the wrong side of the wrong person (they were in STEM not academia). The timer on that was fast and real. They ended up finding another job that would sponsor them almost immediately (not their ideal job, but it would allow them to stay). However, the process is SO SLOW they still ended up back in their home country for several weeks dealing with the administrative stuff before they could return, expensive and annoying. I think they were using an immigration lawyer to help make sure they were doing things the best/fastest way legally possible (it was a confusing mess from my perspective).
Good luck with this.