How can I activate a new Blackberry ID?

im using blackberry z3, i forgot my blackberry id and password. from the website i was able to create a new blackberry id and password however when im entering the same in my phone its not accepting.

Im getting an error msg stating "You can't sign in with a different blackberry id on this device. sign in with original blackberry id used on this device"

Now that i hv a new id and password how can i login to my phone.

You will need to wipe the device, reverting to the out of box state, called a Security Wipe.
You will loose all data on the device, additionally you will loose access to accounts and purchased apps that were set up under the old BBID.
KB33591-How to perform a Security Wipe on the BlackBerry 10 smartphone