Esim isnt working to regist

Hello,
I am from Germany and I am currently living in Portugal for one year.

I would like to subscribe to the Unlimited monthly plan for €9.99. However, I cannot complete the online registration because the website does not accept my German passport number and/or my German phone number.

I would like to keep my German phone number and SIM card active, so I would like to get a Portuguese NOS eSIM with a new Portuguese phone number for mobile data and use both SIMs on my phone at the same time.

Could you please help me complete the subscription using my German passport and German phone number and activate the plan as an eSIM? 

Thank you very much!