"Friend" won't return furniture?

Go to the police department and file a complaint. Generally, they will send an officer with you to try to recover your property. Usually, just having the cops at the door is enough to intimidate someone to hand over property that they know is not theirs. If they don't admit to anything though, the police cannot force them to release the property, nor can the apartment managers open the doors for you without a court order. If taking a police officer to the door isn't enough to recover your property, you'll have to file a small claims case against him.