Bought a new Sears washer which tears up our towels.Repairman says raise water level to keep towels higher.?

the agitator on several machines I have checked have casting marks protruding out on the bottom edge. These four casting projections have ruined approximately $300 worth of towels. Repair man says race water level to keep towels off the bottom but did not fix problem. Sears brochure says satisfaction guaranteed or your money back no one after two years as either fixed the problem or refunded our money but however offered us a 10% discount on a new machine. A big sign in the store says 10% discount on any item over $100. To us this is not satisfactory what do we do next?