I have a Smart "Plug n Talk" and use the Callingnow website for e loads.
You need to be absolutely sure of the number you're wanting to top up - check + double check , also make sure of the network. You don't want a grateful stranger receiving a load . The website is easy to use and these are up to date prices for Smart or Globe. They accept card payments, then confirm by 3 e mails that they accept your order, are processing your order, and finally that the load is successful (taking a few minutes)