Mower Damages Lawn

I have had 3 repair techs come out to my house.  They can see the mower damaging the yard when I turn.  However, because there is no physical mechanical problems and they can't stop it from doing the damage, the cover themselves when they make their reports by saying nothing mechanical is wrong with the mower but the customer is just not satisfied.  They tell me all kinds of problems it could be, but they won't put it in their report.  Therefore when I call customer service, it appears that nothing is wrong, so they won't do anything about the mower.  Its pitiful!!!!