"Your passports will usually be returned to you within 15 business days approximately from the day we receive them. This does not include any time it may take for the Post Office to deliver them."
Check your passport request email and see if there is something like this. I waited 10 more business days. I also sent a inquiry email when 15 business days was past. It took some people 1 to 2 months to receive passport back in Feb/March. Also check your ecase status, if it turns to Decision Made, that means your visa is stamped and you will receive the return mail in a week or so.
Bottom line, it won't hurt you at all no matter when you send an inquiry, especially now you have waited so long. Good luck.
the