General question because I did not find a special area for it: Customer had a fault on the vehicle which was repaired about 7 months ago (Zündtrafo was replaced), exactly the same error occurs now again .. Contract workshop repairs the error again free of charge wants to move out no documents e.g. order confirmation or invoice that the error occurred again and was fixed. Question: Does the workshop have to hand me something ?? workshop argues that e s now everything has been handled on guarantee of the old invoice and therefore I also get nothing. Because assumed this error occurs again and/or involves other consequential damages (event. even engine damage or Kat damage). Then I have nothing in my hand that this error occurred and was fixed twice.