Don't bother sending any merchandize back - you will never get a replacement!!!
Not from my experience. I've bought a mini protank 2, and it was missing the chimney stack. I did an RMA, and they asked for me to send it to their warehouse, and they shipped back a replacement. I also got a tugboat hybrid kit where the posts weren't pressed in (all of them) and spun.. they sent me a replacement atomizer base. Lastly, they sent me a squape-R that had three C decks, and only one was coated... I sent that back, and got a store credit, and got a replacement one.
Three RMAs, and they have each handled them fine. If you send something back, just be sure to contact their RMA department, send the pictures/video if needed as proof, and then follow their instructions. They handle their RMAs by issuing store credit, or replacement. Get tracking numbers. Remember, they're just trying to protect themselves from scammers, which I'm sure happens a lot since they deal globally.