I'd call the service desk and ask where the RFE is in the system. Has it even been filed by the SL office? 2mo to put that in your file is weird. It's not like it's going through one of the main USCIS centers where paperwork is reviewed and approved. It's the SL officer who just puts the missing document note in the file to trigger the RFE letter. I called when we hadn't seen/heard anything about our letter after a week, lol.