How shall I deal with nasty customers on my job?

Three weeks ago a female customer became upset with me after hearing part of a conversation between a co-worker and myself. The customer cursed me for at least 05 minutes to which I reponded in like. The conversation centered around unsupervised children in our store. I know better than to feed fuel to a fire . She was just so wrong in her assumption and later in her accusations that I had to speak up. She threatened to "have my job" and I smiled and said,"don't tease me." Now this female has her sisters and one other friend harrass me on a bi-weekly basis. They are loud and rude and are coming from left field with the reasons as to why they are upset. I have no defense since I do not know these people and I do not understand why they are attacking me verbally with such hatred. How can I resolve this problem without violence when all these women are intent on wanting me to respond physically. Of course, I will not do so unless they touch me first. I would like to put a stop to all this petty behavior before it esculates further. How do I "keep the peace?" Any advise is appreciated.

Hmmm well my advice would be to discuss the problem with your manager or supervisor. Obviously, these people are coming in and disrupting your work and as employers, I am sure your supervisors/managers would want you to be productive and happy on the job. The people who are coming in bi-weekly for the sole purpose of giving you a hard time sound like customers who need to be removed from the store upon acting this way.