PFI-107 Cyan Ink Compatible Cartridge for Canon IPF 670/680/685/770/780/785

I had purchased several of these inks for work. (A good office manager has a backup ink cartridge at all times.) I found out that these inks have been ruining our printer. Now I have to get a new print head, $400. Tried to return the inks but was outside the return-policy window of time. I've now wasted hundreds of dollars.