Can maintenance men come into an apartment without permission?

The apartment complex was changing out fire extinguishers and they sent a notice saying that they will come in and change them out. I called the manager and told them that I would be setting my old one outside and not to come in because I'm not comfortable with people I don't know coming into my home while I am not there. The manager told me that setting it outside was fine and that he would tell the maintenance men not to come in. However, they still came in. What should I do?