Who's Minding the Wires? (1998)

This starts off like a spoofed 1950's educational film about prank phone calls, and goes downhill from there. Instead of prank phone calls, a couple of people apparently call each other by mistake, then other people call a dating/meeting phone line. In both cases, drunken and/or psychotic people scream obscenities at each other. The really mouthy girl continues to rant a bit more after hanging up the phone, then the credits roll.