Hi.   Sorry to hear about the trouble you are having.

I do not know where you can get the firmware..
Goooooogle might.
Personally I would not take that the chance
to load firmware I got elsewhere.

A time ago I wanted to download some software from the Siemens web an also got such message. That was after the European Union changed there policy on "exports". In my case the registration went through  within hours and Siemens gave me access. That was the last time I was asked to register.. although I have to sign-in before being able to get some of the stuff.

Reaction time is normally within hours (under promise, over deliver). The trouble is that it is now the weekend. It would be best if you can register and wait until 12h00 CET on Monday. Else you have to come in contact with you Siemens partner - he must and should help you.

Alternative make a formal request to Siemens:
https://support.industry.siemens.com/my/ww/en/requests#requests

He do hope you get this sorted out soon.
Greetings.
w