Security has harassed me about using a study room ...

Security has harassed me about using a study room tonight, sez I did not reserve clearly I had twice today confronted about using study room. Had to interrupt my online class to go to librarian who apologized for the error. This guy is harassing me please inform him of the policy of the library or inform me that I cannot use an empty study room for more than one hour. I do not understand the issue here.