I just reviewed your order history, and see you bought refill carts for a 7800/9800 printer model, not 7880 as you stated above. Are you in fact using a 7800 printer model?
Your order history shows the 7800 refill carts were purchased in 2011, so you have been using them for several years, in which case I suspect you’re dealing with a worn out chip, and should replace the MK cartridge chip. Chips can wear out over time, or get shorted out from static electricity, so we recommend everyone have a set of spare chips on hand to be able to quickly replace a chip when needed, and resume printing without down time. You can get replacement chips for the 7800/9800 here: http://shopping.netsuite.com/s.nl/c.362672/sc.18/category.122646/.f, and instructions are available on the Instruction tab on the product page.
Please let me know if you have further questions or there’s anything else I can help you with.