When I installed the toner my printer says it is not compatible. Thinking there was something wrong with the cartridge, I ordered a new one but it does the same thing.

Did you buy a genuine cartridge or a refill? If its genuine, then contact Samsung.

Are you certain you ordered the right part #

That may sound obvious but its possible to have one digit wrong and find that number is a valid part number for a different model, that won't fit or work.