I know stories like this really bum the owner (you) out. But, name another builder that you could actually talk to, and have it sent back for a check up. I highly doubt you could get that type of service and/or care from the company named after a car part. I'm not knocking their product, their company started the electric bass industry, but most likely, any big company is going to tell you to go to an authorized repair center. And who knows who's working on your instrument. This P-Bass will go back to the man that set It up and adjusted everything the very first time on it. There's a lot to be said of that type of builder-customer interaction.
Definitely hope it turns out great for you. And knowing Jimmy will personally give it the checkup has got to be comforting in some way.