Digital BW, The Print

I received a set of K7 Neutral inks for my Epson R2400. Today I began
to test and there is a major problem.
The cartridges installed with no problem but the cover of the ink
chest did not close easily as it will with the K4 cartridges. It did
close though.
I selected a test image to print and followed the instructions
enclosed with the K7 inks. The image printed VERY poorly. There was a
great deal of banding as printing began which disappeared as printing
continued then re-appeared as printing completed. In addition there
was a great deal of splotchy puddles at and near the edge of the paper
- Epson's Enhanced Matte. I suspect that is a paper problem with
curling...
I decided to run a cleaning and test nozzle pattern when the printer
decided it didn't want to recognize the "yellow" cartridge anymore. It
did when first installed. I made several attempts to re-install the
"yellow" but it still can't recognize the cartridge. I can see no
problem with the cartridge and the chip is firmly in place with no
visible damage. I did notice the contacts of the K7 cartridge do not
match the positions of the K4 cartridge.
I replaced the K7 yellow cartridge with that of the K4 yellow - the
Epson recognized the cartridge - then replaced the K4 with the K7 and
the printer refused to recognize the cartridge.
Unless anyone has any suggestions, I'm afraid the K7 and piezography
is of no use to me.