on 17-07-2017 14:00
How to cancel here @slawomirbak - It will not be done by posting on here
Lumia 950 Dual (O2 & Sfr) and Z3 Tablet (Three UK)
on 17-07-2017 17:05
Call 202, choose option to leave, give 30 days notice. Voila, job done.
Get your phone unlocked if you have done so
You'll need your PAC to keep your number, see the link by @MI5 above