HP Ink not compatible HP Envy 4500

[AnnaK81]

Hi, My black HP ink cartridge suddenly starting coming up with errors around Oct/Nov last year. It would either say the ink cartridge was incompatible or that it needed replacing. I knew it was a genuine HP cartridge that had previously been working and that the ink wasn't that low to have run out. However cleaning the contacts, checking the updates/ firmware etc didn't make a difference so I signed up to Instant Ink to get a new cartridge. I had the same issue with the black ink cartridge I ordered from there. But after installing this Instant Ink cartridge my printer also refused to print in single ink mode. I basically turned it off in November, sent the ink back to HP and vowed never to buy HP again. I turned the printer back on last week to scan some documents to my PC and low and behold it printed off a couple of documents I'd printed last November (in single ink mode). But when I tried to print documents from my PC they just stayed in the print queue. I Uninstalled all HP software and uninstalled the printer from my PC, did a 'reset to default' on my printer and then installed HP Smart. And the single print mode is now working! HP Smart offered to sign me up to Instant Ink again. So I did. But on installing the black ink cartridge I got the same message about it being incompatible. I've just tried replacing the colour ink (even though mine hadn't run out) to see if that made a difference. It's just changed the error message back to 'the following ink cartridge must be replaced'. Again, I've gone through the help pages. Made sure the printer is up-to-date and that HP Smart updates are up-to-date and cleaned the contacts on the cartridges and printer. Please tell me there's something else I can do to fix this?