Hotel Antares in Oldenburg

AVOID AT ALL COST! READ BEFORE YOU BOOK!
Booked one room for one night stay.
90 euros was charged upon check in as it's my first time staying there. No trust in customer.
Came back to the hotel after midnight and the front door is locked!
Rang the telephone number a few times on the door no one answered. Could not get into the hotel!
Luckily nothing bad happened and I found another place to stay for the night.
Went back in the morning to find out that I should have been given a door code upon check in.
The morning receiptionist offered a later check out and a refund at the check out. And of course the receiptionist who checked me in said she gave me the door code.
When asked for the refund later, the owner said no refund unless they see the proof that I rang the number on the door. No trust.
Show them I rang the number on my phone, they said sorry for my bad luck and cannot issue the refund as promised! Ask me if I want any tea or coffee as compensation.
Their fault = my bad luck??????
The hotel doesn't trust customers, avoid responsibility when a big screw up like this happens. Says it all.