Invoicing Issue

Good morning,

I hope this is the right place where to ask for this kind of help.

Trying to update my invoicing information the form says my invoicing number is not valid/correct, although I enabled the VEIS feature so it should work for international transactions.
I live in Italy and already asked for clarifications to my accountant: everything is right and enabled.
What shall I do to make it work? It is important for me for fiscal purposes. Also I've lately had an issue with my credit card which I had to deactivate for emergency (I had lost my wallet). So I temporarily changed it with a prepaid and then later with the new credit card.

Also during the process I asked for support via chat two times, Italian operators helped me out and were very kind and efficient. After 2 days I've received an email notification saying that my account has been granted with 2 days of free assistance. What does it mean? Is usually assistance for a fee? On the Adobe assistance page I keep reading that the service is free and nowhere there is written that one has to pay for it. How does it work?

Thanks in advance for help.