Hello. I am a physics student in master degree in Germany and I come from Iran. Sorry this is a long story, but I really want to know about my future situations. I am living here about 9 months and I have faced a lot of problems during this time. I got my student visa for city A in Germany and when I came here I went to city B because I had also admission from the university of city B. I did not take any exams there and after 6 month I quit that university and got admission again from a university in city C. during this time the value of iran currency sharply decreased against euro and I faced financial problems and cannot afford to pay my expenses. Now I have to go back to my country and want to take my master degree there and again take a visa for Phd (with scholarship) in Germany after about 4 years later. I also have to mention that I told the landlord company that I cannot pay the last month rent (520 euros) and you can take it from the deposit (750 euros) , but they told me at last we will do this but if you won't pay your last rent we will give the issue to an inkasso and inkasso will do their duty as well and that leads to extra charges for you and negative schufa. I also told them that I will leave Germany in the 1st week of the last month that I permitted to stay according to the contract and will give you the keys in that 1st week of that month. But they didn't pay attention.
Additionally I fined by some other inkassos and I paid all of my debt, except two of them because I took a lawyer for one of them (which my debt was 600 euros) and my lawyer sent a letter to that inkasso containing the legal texts that I have not to pay this amount and said that we should waiting for their response, but they didn't response so far. However I paid that inkasso some amount of money in installments before taking the lawyer.
Now I want to take a semester off and go back to my country and want to apply for a student visa for Phd after 4 years later.
Regarding all of those issues (leaving my studies and not passing any exams, probably negative schufa, etc) My question is how much chance will I have after 4 years later, to obtain a visa again for Phd with scholarship in Germany? I mean would those issues be a problem and bad records for me to acquire a phd student visa again?
Thank you very much in advance for your time and consideration and answers.