As mentioned by many members, to get a prompt reply from them in matters like these, have a catchy subject line. I used " Conformation needed regarding receipt of urgent documents update asked for File ***, UCI***. Give as many pointers as possible to identify you such as Date of Birth, PA, reason for enquiry. They will not go extra mile to identify you and give info. Make their lives easy and they return the favor (atleast they have been nice to me in this regard), specially if you have a common name. I have been doing this since 3 years and get a response next day.
This format is the one I use for directing inquiries to them:-
I am *****, UCI- ***, DOB ****. I wanted to confirm the receipt and updating of the documents I updated a for my application for permanent residency in Canada.
The following are my identifiers:-
1. Status: Principal Applicant
2. Reason: Query regarding receiving of the supplemental documents for FSW file.
3. Name: LAST NAME, First name.
4. Date of Birth
D/MM/YYYY
5. Enquiry regarding updating of documents for application made to PhD stream under FSW category. File No. *****
6. Client ID no. ******
Hope it helps. Its not too late. I am sure they received it via email. Else you have the email history as proof and can argue your case if forbidden happens. You will be ok. Just cover all bases.