Filing a false police report is a crime, but you can't stop them, and the fact that no charges have been filed does not make it a false report. It is interesting that the police didn't come to talk to you, though. Sounds like they didn't take it seriously.
However, I can't help but wonder how you found out, if it wasn't from the police. and I suspect that the people complaining about you have told you that they made a report. As you already know, what these people say isn't necessarily true, so you shouldn't take them at their word.
In order to file a claim for libel or slander, someone has to believe what was said, and it doesn't sound like that happened. You will also want to consider whether filing suit against these people will make the situtation better, or worse. It has been my experience that suing people who make false accusations will generally make the dispute worse - meaning that it could cause them to say a lot more bad things about you. For the time being, they are probably an annoyance which is better to ignore.
Sign up to receive a 3-part series of useful information and advice about personal injury law.