Lodging a complaint regarding the iPhone clear magnetic case

I’ve replaced the iPhone 12 Pro clear case twice due to it just just crackingwhich I notice now is a common problem , I’ve now dropped my phone and the back of the phone has shattered, such a bad product and not protective at all, it doesn’t even covet the entire surround of the phone, , has anyone else had this issue and how do I lodge a complaint and get my phone repaired?