Nothing you can do. That's one of the main problems with Wifi. Anyone can broadcast any damn SSID that they want.
The noise from them will interfere with your own network, but there are some third party connection managers you can install on your clients so they will only connect to certain AP's on a MAC whitelist. It's not a good solution because if someone is being really malicious, they could change their MAC's to match yours, but there's really not much else you can do about it.