Just so you all are aware, refilled inks must FIRST be used within three months. Otherwise the ink may clog the printhead. As long as you use them regularly, then there is no problem. By the way, get your cartridges from a local place as they should honor the fact the ink didn't work.
The reasons that your printer may not recognize the cartridge:
The chip on the cartridge is bad.
The chip on the cartridge needs cleaning on its contacts. (Use the eraser portion of a pencil to clean.)
If the cartridge chip is bad, the only thing you can do is get another cartridge or ask the refiller to replace.