I am sorry to hear you have experienced a leaking cartridge, and have received the photos you sent to Wells showing the small amount of ink in the plastic body of the cart (as you pointed out, there should only be ink in the ink bag, and not in the plastic shel of the cartridge).
After reviewing your order history, I see the 7890 refillable cartridges were purchased between Jan and Feb 2012. About when did you originally fill and start using the VM cart? Is this the first time this cartridge has been refilled, or has it been refilled in the past? I see the VLM cart you had that previous leaked, the leak was noticed when the cart was filled for the first time and replaced right away. I am curious about the use history of your current VM cart, as I have not heard of any cartridge be good and work well for a year, then suddenly begin leaking.
Please let me know so we can help you get back to happily printing.