Of course I do not know what is the cartridge my printer uses, I don't even know the model of my printer!
So I went into the app and looked up the model... Turns out the app only says Deskjet 2600... it does not specify that my printer is Deskjet 2624! So I buy 2 cartridges of 664 black ink (because on the side it says compatible with 2675)
Now I have 2 cartridges of black 664 ink instead of the 65 ink my printer actually uses.
The cartridges are the same, why won't it work on my printer? (serious question)