I'm sure it's very frustrating to you, and I appreciate that you are concerned for the neighbor's dog. However, if possible, I would try to find out if wandering dogs is the norm for the neighborhood. I have lived where this was quite common. If not, and if you do not want to put up a fence at the moment, you might talk to the neighbors and offer to pay for an invisible fence for their dog (if they are willing to have her wear the collar). Best wishes. You are certainly trying to be a good neighbor.