Had the worst experience here a couple of days ago...

Had the worst experience here a couple of days ago.
Arrived there late so there weren't that many people, but that gave them no excuse for the slowest service i had ever received in my life.
We ordered two hot chocolates which were served separately, and waited for a piece of cake for at least half an hour.
The highlight though was that after we payed they gave me back the WRONG credit card.