I agree that its the responsibility for the buyer to ask the critical questions. However, I also feel that the seller has a responsibility for full disclosure. I was more thinking of the OP's situation where the seller was apparently not meeting their end of the bargain and had the OP not asked the right questions, he may have been "mislead".
Again, no. If you discover that the seller has been less than truthful BEFORE you buy the bass, then why would you buy it in the first place? It would seem that the logical person would just walk from that particular purchase, rather than buying the item, only to leave negative feedback for something that happened BEFORE the sale.