YOU SAID:

I was going through a transaction while the people behind me were waiting patiently

INTO JAPANESE

後ろの人が辛抱強く待っている間に取引をしていました

BACK INTO ENGLISH

I was trading while the person behind me was waiting patiently

INTO JAPANESE

後ろの人が辛抱強く待っている間に取引していた

BACK INTO ENGLISH

I was trading while the person behind me was waiting patiently