I reviewed our past support emails and see you experienced an LK cartridge with a leaking ink bag in early March, though from the photos I can see it was not a massive leak, and we immediately sent you a replacement cartridge.
Looking at your support cases, I see you contacted us about missing nozzles in the cyan position back in November, but I did not hear back from you (other than several spam emails) regarding my last message on 11/27....
Are you removing air and priming cartridge exit chambers with ink using the syringe and priming tip (as demonstrated in our video and explained in the current 7890/9890 refill cartridge instructions), or just the syringe? If you're just using the syringe, and your new LK cartridge is leaking from the exit port, it may be that you are damaging the gray rubber exit valve seals- in which case, you will need to 1. replace the rubber seals and 2. get and use the priming tip on the syringe when removing air and priming the carts.
Please be aware (check online to read other 7890/9890 and 7900/9900 users' experiences), these newer printer models have a LOT of mechanical issues, and a leaking cartridge would not cause damage to the parts you had replaced.
When we first got our 7900 printer, I installed the set of Epson carts and started using the machine to learn more about and get used to it. Within the first month (still with Epson carts installed), I experienced several issues and had to have a service tech come out to work on the machine THREE different times to get it working well. Over the three visits to work on our printer, he replaced the selector unit (dampers), print head, capping station assembly (twice) and main board!!!! Since then, it has been working flawlessly for the past nearly two years (with our refill carts and ConeColor inks installed for the majority of that time). Due to the alarming amount of problem reports we've received from 4900, 7890/9890 and 7900/9900 users (many have only ever used Epson inks, but experience problems and contact us for help after getting no support from Epson), we recommend everyone with these printer models protect themselves by getting the extended warranty.
Please let me know where your cartridge seems to be leaking from so I can help fix that problem, if you have questions or if there's anything else I can help you with.
Best regards~ Dana