The colors do deteriorate because they actually dry out over time.  Black cartridges also can dry out, but they don’t seem to do it as often as the color cartridges do.   The shelf life for color cartridges is about 6 to 12 months. It might be that the seller on Ebay did not know about this problem.  If you do a lot of printing, like I do, and use the color fairly timely, say within 6 months or a year, you would not know that this is a problem.  However, the person should have mentioned the age of the cartridge in their item description.  You might want to write to this person and tell them what has happened.  Perhaps they will think about refunding your money.  Of course, if you paid by credit card, and it was a recent transaction, you could alert your card provider that you are dissatisfied with the transaction.  If you paid a reasonable amount and got nothing, you could leave negative feedback, or explain to the seller, that you will, if there is no compromize reached.