That's normal, there's 3 ways you can submit documents to IRCC;
(1) Email them docs on - IRCC.CPCMParentsandGrandparents-Parentsetgrands-parentsCTDM.IRCC@cic.gc.ca (You won't get any acknowledgement using this method)
(2) Submit a webform - This usually takes about a month to get acknowledged
(3) Submit through your GC Key a/c - Click on "View submitted application or upload documents". Here they would allow you to upload requested documents. This is the best method to submit your documents as it will go directly on your file.
You are free to use all 3 of them. Good luck!
Thank you very much.
Sending them via Webform too, just in case they didn't get the email.