My neighbour is a neighbour from hell, what should i do?

Our neighbour is not a nice person, I presume she has never had children of her own, If my kids accidentally kick a ball over they will not give it back, they must have over a dozen balls in their cupboard by now..lol, if the kids bump the fence they yell and scream, i tried to talk to her and she just yelled and swore at me in front of the kids. what do you suggest?