2005 Vauxhall Corsa lots off problems ecu,car not starting etc...

Hi again due to a leak in my car in drivers side footwell plus the engine management light coming on I took car to garage 2 days ago and they still have it.I am concerned that the light came on so asked for them to sort that out mainly..coming back to me and saying that i needed to change the coil pack & spark plugs which should sort it.So me was quite happy bout that,but not to last next day another problem fuel ingection(not to sure)??So ok fine they did that these all showing as faults on ecu and yet again this should solve the problem!!As you mite guess no it has"nt they had for some reason taken my ecu unit out put all back together and now the CAR won"t start at all.he has said they my have disturb something when putting back together???The car was running when i took it there now it is"nt why is??
its like they didnt need to do half off this work they have made it worse then ever...what do i do??