freestyle 2500.registering to a refurbished base station?

I`m trying to register my original handsets with a refurbished base station,(I`ve deregistered the handset ok from old base),but when I try to register it with the refurbished base,I press & hold PAGE untill it flashes then on the handset I press & hold redial & calls & get on display 65- I then enter 1,display now = 65-1 PIN---- I enter 0000 handset bleeps then display repeats 65-PIN.What am I doing wrong?