Broken cartridge

I have been purchasing printer cartridges from this outlet for the last four years. During this time I have always had one cartridge in the printer and another new one on standby. Today my cartridge ran out and I inserted the new cartridge from the box. This cartridge leaked all over my computer and any paper going through. I went to the outlet to ask for a replacement. The sales person commented not the mess in the package from the clearly leaking unit. When I asked for a replacement I was told that this would need to be sent away so they could see what was wrong with it before replacing it. The reason was that I had bought it in February! It very obviously has ink in it, it is clearly defective and yet I must now wait two weeks for this to be adjudicated. The reason? Because I am trying to be astute and not have to replace only once it runs out! This is a disgrace and they have lost my business....how can any company afford this in today's economy?