Selling defective equipment

Bought Black ink cartridge from cartridge warehouse and after I took it back to be refill the first time I was told that the cartridge has been refilled 4 times and cant be refilled. Now my color cartridge was apparently opened by me and is all so a fault with. Me as person do not even know how to open the cartridge let alone that you can open it. Not very ethical business practice and public should be warn about there practices.