Why don't all you people get off your soapboxes and have a little empathy.
First off, the guy was 79 years old. In this day and age many young people belittle older people when it come to tech such as cell phones.
Next, how have many of you felt when you realize that you have to sign a 2 year contract just to have crappy phone service, or got some $500+ bill from a cell company that was clearly their mistake, or found crazy overage charges on your bill because of a misleading explanation of how overage works, or even the most common one, a dropped call.
The guy was old and probaby felt ripped off by this younger tech generation and did the only thing he knew how in order to fight back.
It's funny that the store can ban him from coming in, but somehow I bet the billing dept didn't put the ban on taking the old mans money.