As others have said, this is sadly a pretty normal experience with running FC's. The cause is typically someone who has been rejected, removed, or left on what they feel is a negative note getting salty. They tell their friends and impressionable strangers who often get salty, too, and keep the rumormill going, who tell their own friends and other impressionable strangers, etc. Of course, there are other causes sometimes--other FC's jealous because they feel they're in competition with yours, random ass people who feel your FC is doing something "wrong" and that they could run it better than the current leadership, people who have had a negative experience with a single one of your FC members (past or present), the list goes on. People will cause drama about the pettiest of things.
If the rumors are concerning you, you can look into it to find out what is being said, by who, and why. Once you find out who is at the source, you could try talking with them, but that's honestly probably a lost cause. It would be better to just find out what the rumors are to see if there's any truth behind them and see if there are improvements that could be made to your FC and its image. With level one alts messaging you to say "people are saying bad things" and giving no further detail, though, it just sounds like one of the people who feel they've been wronged by your FC is trying to start drama and upset you, rather than a helpful player trying to give you a heads up.
So the best advice I can give is to keep doing the best you can with your FC to make it a positive environment for its members and the people around it. Less rumors will start/spread that way, and people will be less likely to believe the rumors when they hear them. And remember that in the end, anyone who's going to look down on your FC or avoid it based on completely unfounded rumors is no one you need around you or your FC, anyway.
If the rumors are concerning you, you can look into it to find out what is being said, by who, and why. Once you find out who is at the source, you could try talking with them, but that's honestly probably a lost cause. It would be better to just find out what the rumors are to see if there's any truth behind them and see if there are improvements that could be made to your FC and its image. With level one alts messaging you to say "people are saying bad things" and giving no further detail, though, it just sounds like one of the people who feel they've been wronged by your FC is trying to start drama and upset you, rather than a helpful player trying to give you a heads up.
So the best advice I can give is to keep doing the best you can with your FC to make it a positive environment for its members and the people around it. Less rumors will start/spread that way, and people will be less likely to believe the rumors when they hear them. And remember that in the end, anyone who's going to look down on your FC or avoid it based on completely unfounded rumors is no one you need around you or your FC, anyway.