Your job is to protect your dogs. Print out the information regarding the laws in place, highlight it, go over it with them and tell them that if you see their dogs unleashed and off their property again you will call AC and continue calling AC until they learn to properly contain their dogs on leash, in their home, or in an outdoor enclosure like a kennel. Then make sure you follow through. Sometimes, because AC often comes out much later, it helps prove to AC there is a problem if you get pictures or video on a cell phone or digital camera. You're being very reasonable about the situation. If they have to pay fines and fees or lose their dogs then that's their fault for refusing to follow local laws and for being bad neighbors and dog owners.