It's frustrating to hear that you've been selling on Amazon for such a long time without being eligible for the Buy Box, especially for items like books where competition can be stiff. However, there are several steps you can take to try to become eligible to sell books on Amazon and potentially win the Buy Box:

• Check Your Metrics: Make sure you're meeting all of Amazon's requirements for eligibility. This includes factors like maintaining high seller ratings, low order defect rates, and fast shipping times. If there are any areas where you're falling short, work on improving them to increase your chances of eligibility.

• Optimize Your Listings: Ensure that your product listings are optimized for search and conversion. This includes using relevant keywords in your titles and descriptions, providing clear and accurate product information, and using high-quality images.

• Competitive Pricing: Price your books competitively to improve your chances of winning the Buy Box. This doesn't necessarily mean offering the lowest price, but rather offering a competitive value proposition in terms of price, shipping, and customer service.

• Maintain Sufficient Inventory: Make sure you have sufficient inventory available to fulfill orders in a timely manner. Running out of stock can negatively impact your seller metrics and reduce your chances of winning the Buy Box.

• Consider Fulfillment by Amazon (FBA): Utilize Amazon's FBA program to fulfill your orders. FBA sellers often have an advantage when it comes to winning the Buy Box due to the reliability and speed of Amazon's fulfillment services.

• Contact Seller Support: If you're still having trouble becoming eligible for the Buy Box, reach out to Amazon Seller Support for assistance. They may be able to provide further guidance or insights into why you're not eligible and what steps you can take to improve your eligibility.

• Explore Alternative Channels: While Amazon is a significant platform for selling books, it's not the only one. Consider diversifying your sales channels by selling through other online marketplaces or your own website.

By taking these steps and continuing to focus on providing excellent customer service and competitive pricing, you can improve your chances of becoming eligible for the Buy Box and increasing your sales on Amazon.