Hi Mitz,
I suggest you write them a letter to request for the waiver of the FBI clearance stating that you stayed in the US for less than 6 months and it takes 8 to 12 weeks to process an FBI clearance so you might not be able to comply within the prescribed deadline. Ilagay mo lang sa letter mo yung dates ng stay mo sa US, kung may proof ka (ex. stamp sa passport mo ng arrival and departure to/from US), i-attach mo na rin. At the same time, mag-request ka na rin ng FBI report para tumatakbo na rin yung request habang pending pa yung approval ng request mo for waiver.
Ganyan ang ginawa ko nung nag-require sila ng Saudi police clearance for my husband. Matagal ang processing kaya nag-request ako ng waiver. Although hindi ako nakatanggap ng approval pero naka-receive naman ako ng request for passport, so ibig sabihin approved ang request ko.
Good luck!