Mercedes A160 auto gearbox

I had a problem with the auto gearbox on a Mercedes A160, and took it to this workshop for repair. The next day I was told that they are unable to fix the problem, because they dont have the specialist tools for the repair and that I need to take the car to a gearbox specialist. I subsequently had an auto electrician look at the vehicle, who then simply reset the OBD error codes on the gearbox and told me that the gearbox has too little oil in it. I then had the gearbox oil level checked and refilled by another workshop, and the vehicle has been driving perfectly ever since, with no further error codes. Anyway the resetting of the codes and the filling of gearbox oil this workshop could have easily done, but for some strange reason they chose to tell me that I need to take the vehicle to a specialist workshop because they cannot fix it because they dont have the specialist tools. And btw the other workshop used standard workshop tools to drain the oil and refill the gearbox. The strangest motor industry experience I ever had. I have found other better and more helpful options, which there are still some of.