"the light" doesn't actually convey a lot. Which light? One assumes the engine gone management light but who knows? You do but no one else.
One assumes the garage read the fault codes stores on the engine management system when they reset the lamp. What were the code(s)?
Vauxhall Corsa is a popular car and has an enthusiast following. You would do well to search out some of the enthusiast forums and post your questions there