Hello. I am Maryam and I'm accepted for a PhD position in Germany. I'm not a native speaker and in my country people rarely speak English, so I'm just so worried to speak or write in an inappropriate way.
I just got my visa and because of the delay in organizing my visa due to some local problems which were out of my control, once I lost my position. However my supervisor told me that he understands my situation and as soon as I got my visa we can discuss about this issue again. After I got my visa I informed him and he told me I should wait until he organize somethings in his lab and he let me know as soon as possible. In order to get my visa I have deadline from Embassy to hand in another acceptance letter with new start date before 27th Nov. The other possibility is to write a letter address to Embassy and just update them about the situation. I want to write a letter to my supervisor and ask him to send me another acceptance letter or send a letter to Embassy or send me a letter addressed to Embassy so I can go and hand it in personally.
Here is my letter. Could you check it for me, if there is any grammatical errors or if it is not formal enough.
Dear Mike,

regarding my visa, in order to complete the procedure I'm supposed to hand in another acceptance letter claiming the new start date of the project before 27th Nov (fortunately this time the scan version of the letter by email is sufficient).

I understand that this whole process made a lot of troubles for you and as I mentioned before I'm really really thankful for your patience and understanding, in case there is still the possibility for me to join your lab and it take longer to decide on details e.g start date, I appreciate if you could kindly update German Embassy in Tehran about the situation via this e-mail Ms X ..... before 27th Nov. This can be also scan of a letter addressed to German Emabassy which I personally go and hand in.

I'm looking forward to hearing from you.
Sincerely
Maryam