Smeg oven (dont know model)?

just had my element replaced but as soon as repairer left the clock just flashes and oven did not work at all, not even the fan. There must be electricity getting through as the hob ignites and the grill to the top small oven works. I was not there at the time, and the repairer assured my daughters that when i get the timer working the oven would work. Now, surprise surprise i cannot get hold of the repairer and have a timer that just flashes and no working oven. Any suggestions would be helpful, i realise the idiot repairer needs strangling and i should have been there myself.