Managed to Get a Japanese Visa

This is my story of last night. I think it is more natural to say "This is what happened last night" or "This is what I did last night."

I had just called the Japanese embassy in India. Since one of my Indian friends will come to Japan, I wrote some documents such as an invitation letter for him. He tried to apply for a Japanese visa once but he failed.
He asked me to resend (him) some documents that the Japanese embassy had requested, to him again. (It is a little strange to put "to him again" so faraway from the verb. It is better to change the verb from "send" to "resend" so that you don't need to fit "again" into the sentence.)

I immediately got a letter about a tax payment certification immediately and sent it by DHL last week. It cost 5,510 yen. How expensive!

I was surprised; he got my parcel the following day.  It is a little strange to use "he succeeded" here because your friend's actions didn't affect when the parcel came.

Today he had an interview at the embassy and he was approved to get the visa.
However, he was told that he will get his passport tomorrow. His flight was scheduled to depart early tomorrow. (Did he buy his flight before the interview at the embassy? If yes, "his flight was scheduled." If no, "his flight will be scheduled.")
So I called the Japanese embassy in India to ask one of the staff members if they could give him back his passport.
However, I was told that it was impossible because the other staff members would proceed something in his passport tomorrow.
Finally my friend canceled his flight and changed his depature.

Thank you in advance for your corrections.

That sounds like a frustrating situation! Is your friend still going to come to Japan? I hope he has a good trip when he is finally able to visit!