I locked my phone from another device using the ADM now my phone wont accept the password to unlock, been trying for 4 days.
The ADM is not downloaded on my mobile as an app is this the problem?
Nope. I had the same issue and google support gave me no answer but factory reset, as did the samsung representative i spoke to. I have a galaxy note 3. You can try unlocking from "find my phone" on samsung website if you have a samsung phone and have the services set up... or try reseting password through another phone with ADM... but if not, you'll have no choice but to factory reset, which is what i had to do. Sorry if that didn't help you