How get stimulus check if old mailing address no good?

I moved last November across the country. The last address the IRS had for me is a PO Box owned by a man who is very ill, and as it was a business PO Box, none of my mail can be forwarded from it. I filed through Turbotax a few weeks ago, with my new address, but I never set up a bank account with the IRS. The IRS system will NOT let me set up online because for some weird reason they can't verify my phone number?! (Verizon cell phone I've had for over a decade). So I'm sure my check will be mailed to that old PO Box, and will just sit there for 6 months or a year -if it isn't stolen. Also, if the IRS sends a verification letter to that address, I can't get it! Help! Thanks.