USCIS should have sent you a mail/email/txt receipt by now.

My guess is that your application didn't make it or got misplaced. Call USCIS again and ask them to check again. If they don't have it, or if they claim they did not receive it, send a new packet.

I think at this point your application will not get renewed in time. You can contact your congressman once you have a case number. I don't think anyone can do anything if there is no case number.

Have you checked if the check has been cashed?