i am selling for 5 months with out any problem and 4.9 feedback .
Hello,
Your current sales volumes are not supported by buyer feedback or an established sales history. As a result, we are reviewing your Amazon.com seller account. During this review, you may not sell on Amazon.com. Funds will not be transferred to you but will stay in your account while we review it. If you have any open orders, please ship them.
To learn more about account reviews, search for "Velocity Limits and Account Reviews" in Seller Central Help.
That message is as a result of your sales to feedback ratio. If their to wide, i.e. too many buyers not leaving you any feedback could imply to Amazon buyers are perhaps neutral with the product and service you've provided. Neautral doesn't bode well with Amazon, so you need to always ensure your service is at the top of its game.