As I Understand you are having trouble with redeeming HP Rewards on all 4 occasions of Ink Cartridge replacements,
Don't worry as I'll be glad to help, however, to provide an accurate resolution, I need a few more details:
Have you checked the FAQ's available on the HP Website regarding the HP rewards program?
If you haven't, here's what you need to know: Click here
If you have issues with the above link or proceeding with redeeming the rewards as such, simply Contact HP using the below instructions and keep me posted if you have any trouble as I'd like to ensure you have what you need before we let go of each other 😉