I think it's a ploy. I shared your comment with a friend who works in a call center and agents have been known to resort to shenanigans to get rid of a call (or just take a break). In her specific case they had a combined support/sales line where you get commission for sales but not for support, so if someone is just ranting at you about some issue you have no power to fix, you might be tempted to unplug your phone's Ethernet cable and re-roll for a new call that might be sales instead of support. Could easily be the same thing for cell phone providers, though this was a hotel chain.