It's too soon to call in a service engineer...
It may well be that the cooker has been accidentally set to auto timed cooking - reset the clock - switch off the power and back on again - the clock will flash - depress and hold in buttons 2 & 3 from the left and set the time (any time will do) with the plus and minus buttons.
Then if that doesn't work consider an engineer.
Good Luck...
May 2017