I have a Bernina 1230 and just bought a 750QE. I have NEVER had this happen to my bobbins. I would be taking a fabric run to the dealer (an hour is not that bad!) and having them check it out again (at their expense). Then I would let it slip in appropriate circles that their service is not the friendliest. OR, knowing me, I would drop hints like, "Oh I hope that your day gets better." OR "sounds like you are having a bad day or are you always grumpy?"
I refused to deal with the Bernina dealer in a nearby town (an hour away) until they finally got a new WONDERFUL dealer in the same town.