Before hiring an SEO expert as a seller account holder you must know that Amazon always tracks your product customers. They keep an eye over the SEO and purchase, is that selling to a genuine customer or unfair SEO work provided by someone? If they get any clue make sure you are going to get penalized your SA. So before starting to work make sure that the freelancer is well known about the latest Amazon algorithm. Have well knowledge about how Amazon tracks customer identity like operating system ID, Mac ID, PC physical ID, Importance of user account, and how to escape that. Strong consciousness about proxy and tracking malware, how amazon identifies browser & find out browsing history, and caught fake purchases. How to provide SEO work as a genuine customer shopping from Amazon and behaving as an ideal customer according to the Rules and Regulations. If the freelancer makes any mistakes of those, surely your SA gets in danger. So be very careful about Black Hat SEO and Purchase.