These guys have no idea what they are doing

I sent my MacBook-Air in for repair after I accidentally deleted some of my MacOS system files. These idiots sent me my Mac back to me with a small slip informing me that they could not repair my device since they could not open it up. After chatting with one of their service managers I then sent the device to them again . This time I opened the device for them since their technicians apparently do not know how to wield a *****driver. After some time I received a quote from them of around R28000 to fix my device. I purchased it brand new for R22000. They only had to reload its operating system as simple as that. I declined the quote and managed to fix the device myself by following a few YouTube videos.