Most of the time over the last 11 years I've been using QBO the telephone support does notssupport the mobile application other than to remove and reinstall or update the application.  They are pretty much useless.

I did find a workaround for this issue specifically.  I typically start an invoice by selecting the customer from my customer list, click the plus sign and select invoice.  I tried to select create invoice then populate the customer.  That seemed to include the customer name in the "bill to" area of the invoice.  I remember having to do something similar when the app quit creating invoices for a time.