No Option to "Add a Case to Your Account" on USCIS.Gov account

I filed a paper application I-90 as a representative with a G-28 Form. We received the Receipt number on a notice and the Online Access Code via a different notice. I already had a USCIS.gov account (which I used to submit a FOIA to get past immigration records for my client). The existing account doesn't let me add a case to my account. So I created a new account, with a different email address to try to add the Online Access Code to link the paper application. When going through the account set up, the website claims it cannot find the Online Access Code I input, even though it is correct and it has not expired. I tried speaking with Emma, and a live agent through chat and was told to go through the tech support to request an Online Access Code. When you select that you need a new OAC, it sends you here: https://www.uscis.gov/tools/uscis-tools-and-resources/online-account-and-technical-support/how-do-i-get-a-new-online-access-code but this tells you to add a case to your account under the my account menu drop down. I do not have that option on my existing account AND in setting up the new account, it tells you that you have add paper applications at the outset or you won't be able to in the future. I think I am screwed. Can anyone help me? Of course, USCIS scheduled a biometric appointment in 3 days and I need to request disability accommodations.