MasterCard stopped issuing through the supplier of those cards. You can use Coinbase and have the funds deposited into your account or Lykke works well to deposit to your bank. There are more and more off ramps all the time depending where you are located. In the USA many use the Shift card.
I see that you're in Germany. Try and message @uwelang
Thank you for your answer @kus-knee ;)
Would love to know exactly why they stopped, maybe new laws or something. Anyway, indeed it's not that complicated to withdraw to a bank account. The card would have also be rather a test ;)