my baxi 105e combi is not working as it should?

had my baxi 105e combi serviced and repaired after having on going problems with the heating and hot water(only a few days ago) got a man from b.gas to fix it. worked fine for about an hour until i had a very cold shower, all the temp l.e.d's went out and the pilot light went out, don't know why but it seemed to right itself after about 20 mins and heating and water was fine, all the temp leds came on but it seems to happen at least a couple of times in as many days.......... please help.. damsel in distress