Based on the pic from website, does not seem to be a boss for the feet screws to secure to. Therefore, it looks like it slides out from the back. Look for something on the back that needs to be moved to allow the cover to slide out on rails. Also feel around to see if there is a screw under the sticker. I feel your frustration on receiving something with a rattle in it. Take your time, you got this.
Monday you could give their help desk a call or send an email.
Service Center
Rafael Lopez
262 East 37 Street
Hialeah FL 33013
USA
Tel: +1 (305) 218-5381
Email: helplopez6129@gmail.com
