Has it pulled through the stirrup? This is a common, and very dangerous, fault with non-Shimano brakes. Shimano seem to use harder metal. Even so, I'd probably swap out V-brakes after a few years' hard use.
On a related subject, there was a BSO in the work bike shed this week with disc brake calipers and no discs on the wheels, i.e. no brakes at all. As it had gears and a freewheel, I wonder how it works. It may be that the rider is exceptionally skilled at jamming his foot between the rear tyre and the frame, something the local BMXers have adopted.