My sister booked this hotel she gave me a key card...

My sister booked this hotel she gave me a key card but they refused to let me in, I politely asked if I could call her and resolve the situation in the lobby as it was 4am cold and my friend was ill but they still refused and said they refuse to let anyone in without a key card even tho the guests themselves didnt take the key card so they said they wont let them in... They let in one of my friends who came 15 minutes earlier who wasnt a guest so I dont see the logic, and has been treated unfairly. Didnt ask me my name to see if I was registered or anything.