Slam clunk

WHEN my 2004 Mazda3 Maxx hatch went in for its 40,000km service, I reported a clunking noise I could hear when selecting drive and reverse. The warranty has expired, but it's still under the extended five-year warranty. The dealer told me a driveshaft washer was needed to stop the noise and would cost about $600. The service staff member was helpful and asked Mazda to cover the repair because of the low kilometres on the car, but this was denied on the grounds there was no safety issue and it didn't affect the performance of the car and wouldn't wear out any quicker et cetera. Does this sound right?