E-invoice for multiple customer numbers

The e-invoices have no longer been processed correctly for several months. When I switch my three invoices to e-invoicing, two have remained “In Process” for weeks. Logging out of e-banking and logging in didn’t help. Both the shop and the call center were unable to help. What’s interesting is that it worked without any problems before and suddenly it hasn’t worked for two months.

How can I set up multiple invoices via e-bill?