I have a Optel DSM and working from the original instructions, to set the time the crown is depressed, when depressed it engages a switch which has four positions, one normal, one to advance the hour, one to advance the minute and one to pause the watch, the watch goes into pause mode when it is released from the minute advance position.
It sounds like your watch has got stuck in the pause position, I am not sure how to rectify the fault but thought this might help to at least point you in the right direction.