Seeking Information about English Concessions & Turkey

My great-grandfather Johannes Kloster in 1934 with his wife and youngest son Ivan, and the eldest son Alexander with his family, fled from the USSR. They crossed the Pyanj River on a raft, crossed through Afghanistan and Iran they arrived in Turkey. Great-grandmother died on the way. In Turkey in 1934 they applied to the English concession. Alexander and his wife and two children were allowed to move through England to Canada to wife’s father. Great-grandfather and his youngest son were not allowed to move abroad. The given reason was that their family was not complete. And they got lost in Turkey.

My grandmother remained in the USSR and all her life she wanted to find out what happened to her father.  Maybe someone will help me by answering my questions:

1. Why didn’t they recognize them as refugees?

2. How many English concessions were in Turkey in 1934?

3. Do you think Turkey deported back to the Soviet Union?

4. On which way they could move (Railway)?

Thank you!