The point remains, if I was a customer who had planned my budget on the previously lower rates, this move’d be very disruptive.
Herzner is an established player, not a startup, this either shows a lack of regards for customers, or that they aren’t very well run.
If you need long term price security, than you need to get a long term contract. The big cloud providers will give you that if you pay them enough in advance, but probably for at least 50 times the price per TB.