I wanted to register my LoRa Gateway, but I cannot add a free Discovery subscription. I filled in my name, phone and card number, accepted the Terms and condition , but the confirm button remains blank. What am I missing?
Start with/use TTN 1st?! 
Add to the community and leverage/expand what already exists. Will depend on what your ambitions and plans are… just saying! 
As you have chosen to go with a commercial instance, perhaps you could use your support contract? Oh, wait.
The forum is rarely visited by TTI staff at the weekend or out of hours so you’ll need to liaise with them on Monday morning office hours CET.