Mercedes-Benz 24/7 on-call breakdown service is useless!

I called Mercedes-Benz on-call 24/7 breakdown assist to sort out two separate vehicles with battery problems. On two separate occasions they sent technicians to diagnose the problem. His diagnosis on both vehicles was that the battery is fine and he cannot send a breakdown to assist me. So I had to take the vehicles myself to the Mercedes-Benz branch where they discovered that the battery is indeed faulty wasting my time and resources. They did confirm it was a battery problem and ended up replacing it. What was the point of having the on call 24/7 breakdown service?