Crazy returns?


If I sell an item for $120 and AMZ charge me with a sale fee of $27, why when the client makes a return for this order AMZ only returns me $16 for that sale tax? And not only that, they also charge me with a customer return fee between $4-$7 per return order. Sorry for this questions but I’m a new AMZ seller, Can someone explain to me how do losses in returns works?
Thank you


27 US dollars is the sum of your sales commission and logistics fee. The returned 16 US dollars is the sales commission charged, while 4-7 US dollars is the logistics fee returned