Single handle.Do not know the brand.Installed 8 yrs. Ago and started to leak.Removed handle, the cover plate and unsrewed the next piece, actually 2 pieces, they unscrewed
By hand.I do not see anything that looks like a cartridge.

If you could use your phone and take a picture of the faucet as it looks when it is all together and one of how it looks when you have it apart we might be able to help you.

.I do not see anything that looks like a cartridge.
Did it have a ball,(see image) like Delta valves have? Let me know, Tom