Help…Court ways initiated!

Hello, urgently need help or experience. Has sold my audio about 1 month ago. Has previously bought it through an audio dealer who made a brokerage sale. The current owner now accuses me of having fraudulently concealed an accident and he would go with opinions to his lawyer. 1. I was not sold the car as an accident car, was search service maintained at audi/vw & had an oeamtc pickerl from the previous owner. 2. I had in my possession (1 year) no unf all not even bumper or similar. Had also received from me a service in audio operation as well as a pickerl whereby I was both called no accident damage. 3. vehicle had no technical problems. Only optical traces of usage from the previous owner (wheel run scratched slightly rusty, lower turf slightly rusty, since older master) 4. fzg was also sold from my sight at a not too high price Well what can happen to me? Sold my fzg without warranty and gara ntie and as tested and visited. I am from Ö if this is relevant, ask for help Thank you