I am in exact situation like you....
AOR 29th Jan 2019. My file is in CIO Sydney, NS and POF needs RR (Review Required). Until Jun 2017, I was working in the US. Later, I moved to India as company transferred me. When I asked my American Bank to issue a letter in IRCC prescribed format, they said "no" due to security concern (to avoid any fraud) because letter was suppose to be mailed to my India address. So I produced an affidavit and notarized past 6 months electronic statements. This affidavit is under "Review Required". I have provided Letter of Explanation along with my salary slips from the US to prove that account was my salary account and it is still active. Ironically, with same affidavit, I received PNP nomination without any issue or single question!!
I came to know about this when I applied for GCMS notes on 6th June which I received on 9th July. So I took a preemptive action and sent another letter of explanation with latest bank statement to prove that the account very alive and it is genuine account. This letter and bank statement has been received by IRCC but there has not been any action so far.
I called helpline on last Monday and agent told that file is in the queue and officer will review it but there is no visibility of timeline. I asked to send a reminder to officer because it has been more than 6 months but agent denied and asked to wait until officer review.
So bottom-line is that there is no way to expedite the application and we should wait patiently. I know waiting is much more difficult than one can imagine..Prayer for all..