S 500 W221 Gear damage

Hello… Something really bad happened to me. Last week I was in Dortmund, had to do something there… There I drive on the highway with our W221, lights up a lamp. – There comes an error message with gearbox workshop. I had to put back 120 KM. So I somehow managed to get home at snail speed. When I left the car, came the alarm message. Gear damage and that with a w221? BJ. 06. approx. 77,000 km down. What me int you, how much is that going to be?? I’ve had a gear damage before, then at the 400 cdi ML. But that had been vulnerable anyway… but with a S-class?? Is that normal? I hope someone has some answers ready. MFG