cartridge

I am new to DIY plumbing projects. I am replacing the hot water cartridge in my shower but can not get it installed correctly as no matter what I seem to do the hot water will not turn off at the faucet once I turn the hot water on in the basement. I am open to any and all suggestions...

Hi all, Bought a house in 2016 and have a leaky faucet. Plumber told me the cartridge needs replacing. It is a relatively new sink but I cannot find model numbers anywhere. I will try to contact the sellers to see if they have a clue where they bought it but they were not very friendly/helpful...