Always light is on all the time

Question

my Sanyo EM-Z2100GS is brand new.just use for one week.and now it doen't work.food is still cold......but u hear the sound of rotating...main problem is why the microwave light is on all the time..you cancel and close the door still lihght is on.you stop and close the door still light is on.what's wrong with this??please help me.