I am a freelance in Germany ("freiberufler" is the term here). I have developed a website for a Spanish company and I have written them a bill for it.
Now they are trying to put their finances in order and they are asking me for a VAT number with the format "DE123456789". I dont have such number. I only have a number with the format "11 / 111 / 11111"
After some research I think Ive learned that these numbers are only given to GmbH which I am not.
The customer insists that I have to provide him with this number. How should I proceed in this situation?