Sounds familiar. I have also had heaps of trouble with refilled cartridges and 'compatibles' which were not.
If you use genuine cartridges you can expect a replacement without question. While Cartridge World is good, some machines just don't function to well with other than the real thing.
Why is it necessary for each manufacturer to have such a large array of different cartridges?
As a printer can instantly detect if the cartridge is genuine, I almost think that printers are now made to 'play up' after a while, but that would be too cynical. Or would it?
I have recently bought my sister-in-law a completely new Canon MP210 printer (fair do, on special) for less than a new set of ink cartridges would cost. Crazy!
Hunt around for machines that use cheaper cartridges and send the opposition an e-mail to say that you've gone to *the other make* because they have cheaper cartridges.