In April, Kelly sent you a new cartridge, a bottle of 220ml PiezoFlush intended to flush out that position, and a bottle of new Orange ink to use.
The new ink formulation is fine.
1) Did you flush out the ink channel in April or more recently with PiezoFlush?
2) Did you only replace the old ink cartridge/ink with the new ink cartridge/ink?
3) Did you pour in the new ink into the old ink cartridge?