We have been working with artists in our studio over the past few weeks, therefore I haven't been on my computer as much as usual, and apologize for not responding sooner.
Please verify the air vent hole of your VM refill cart is open to allow ink flow. You cleaned the capping station and wiper blade, but did you also clean the bottom of the print head?
If the level of PiezoFlush isn't going down, and nothing is printing in the VM section of nozzle check prints after several cleaning cycles, then something is restricting ink flow from this channel. Things that could cause this are: the cartridge preventing ink flow for some reason (sealed vent hole, not enough ink in the exit chamber, not enough ink in the cartridge body, old/dried cartridge, poor connection with the printer, or damage/defect such as punctured side membrane, or something else effecting flow thru the cartridge areas), and clog/blockage or bad seal somewhere in the ink line, damper or print head. Particle build up in the dampers will restrict ink flow over time, often showing in the magenta and/or yellow channels first, since these are the thickest due to the natural pigments used (this is true for all pigment inks, including Epson).
Please let me know so I can try to help resolve this and get you back to happily printing.
Best regards~ Dana