Just kidnap and torture the bitch. Drive her over to Jersey City, put her in concrete blocks and dump her out in the Atlantic. If you're wondering why Jersey City, the mob does a good job controlling the cops there so you can move the victims around easier than any other place with a dock.
I dont know about physically harming this woman. I mean...does a bunch of mean words warrant execution and/or violent beatings? This has been going on with the neighbors for 3 years...so I think a just punishment is for them to be tormented with death threats, late night harrassing phone calls, and notes on the car for 3 years. I really do not think the woman is sorry for what she did, they are only saying sorry because they do not want the harrassment on them to keep going. They can dish it out, but they cant take it.