After reviewing your order history, I see you bought a set of R3000 refillable carts and ConeColor inks in 11/2012, and another set of inks and carts last month. Are you using one or two printers? If one, what set of carts are you currently using?
When you experience banding and missing nozzles, are the missing nozzles usually in the same color position(s), or do they move around in different positions? Do you recall about when you first noticed this issue, and what happened around that time that may be a factor?
Have you manually cleaned your printer's capping station, wiper blade and/or bottom of the print head? What is the humidity level in your printing environment?
If you haven't already, I recommend you check out our printer maintenance and cleaning article, which includes several helpful cleaning procedures as well as other tips: http://www.inkjetmall.com/tech/content.php?133-Printer-Cleaning-and-Preventative-Maintenance
I hope this helps. Please let me know if you have questions, your results, or if there's anything else I can help you with.
Best regards~ Dana