I had a similar issue to you. These are the steps I took:Received a letter saying:
Client Information: Receipt of information from client Please provide additional documentation for all your claimed work experience. You may wish to submit T4's and/or paystubs as supporting documents.
This must be received by: 2022/06/30 Please note that the requested information/documents must be received within 30 days from the date of this correspondence. Please upload these documents to your MyCIC account.
If we do not receive the information/documents within 30 days, your application will be assessed based on the information we have on file, meaning your application could be refused as incomplete
But there's no link in MyCIC account to upload the docs shall I use the webforms instead?
1. Upload to webform
2. Send to the VO email
3. This one is peculiar..
I accessed the CIC portal via mobile browser, didn't see the section to upload Client Information. However, after refreshing a few times, suddenly the layout of the checklist changed from mobile to desktop, and the section to upload Client Information appeared. This is after approx. 10 refreshes. Try this and see if it works for you.