Sounds to me like just another joker posing as a "luthier" or a "guitar tech" trying to drum up some business for himself. Don't forget, they don't make money by recommending easy, cheap fixes. They don't like workarounds they can't charge much for, and they especially don't like DIY solutions that circumvent your need for their services altogether. Their field is no different than auto mechanics, plummers, HVAC contractors, etc., of which many are simply dishonest, or even worse, unskilled. Find another person to work on your bass, or go on YouTube for DIY lessons.