When I worked for ~BT&T~ we had a daily caller, Debra K. (I quit there in 2008 and still remember her name!) one day she would call and say how terrible we were, the customer service was horrible, always escalating to a team lead. We all dreaded seeing her number pop up. On other days she would praise us saying how wonderful we were with our services and customer service. It got to the point she was calling multiple times a day and in an office of about 300 EVERY agent knew her. She eventually called and complained so much that my team lead, with whom she was on a first-name basis by that time, had to file a restraining order on her. We were no longer escalating the calls, just hearing her rant. One day her son finally calls in and explains she has mental issues. Oh really? No kidding! She kept calling lol. Oh and we still had to try and upsell every time!