Have you manually tried to download your graphics driver from Intel directly? If not I'd suggest trying that next. If you need help finding or identifying the correct driver let me know.
Also for more information, did they explain what type of repair they did on the laptop at maintenance?
Yes, I downloaded directly from Intel and no success. He explained but I didnt understand lol. Now my laptop in at the maintenance again. Hopefully he will be able to fix that. Thank you!!