on 12-06-2015 05:02
Yes you will be able to top it up anytime you want either online, over the phone, buying vouchers or at the ATM machine. How often you top up depends on the tariff you choose.
on 12-06-2015 10:22
OnePlus 6 (O2 & Sfr), Z3 Tablet (Three UK), iPhone 8+ (EE)