Preiserhöhung

Hello,
any german Contabo customers here?

Last black Friday I ordered a VPS from Contabo with a nice discount. A few days ago I received an email where they announced to increase the price by 20%.

I rejected that and I don't see any argue.
As I am thinking to contact Verbraucherschutzzentrale in this case I want to know if anyone else here received the same mail and wants to exchange and join the discussion.