How do I get a refund/replacement for a defective ink cartridge

[ELM62]

I recently purchased an ink cartridge for my HP photosmart C4780, from a local Walmart (who won't take back the defective cartridge). The cartridge was not only empty but the tape to cover print head was missing...and both the foil package and box were sealed before I opened them. Who do I contact (since the printer is considered 'retired' on HP's site.

[Valsimot]

The seller sold you an defective product and won't take it back. It doesn't matter if it's a ink cartridge or any other item the are selling, the seller is responsible for defective products they sold, not the manufacturer.