My mother is currently using the old school flip/clam shell phone on the Telstra Simplicity prepaid sim. She's said she wants to start using a smartphone, which I said she'd want to start looking at others plans/prepaids, given the bit of data she'd then be using. I've got her an 64GB iPhone 5S which I bought off a work mate (for $50 after replacing the screen protector with a decent spigen one, and a bit of a clean, it looks brand new), and I'm thinking she'd be best off on the Aldi $25 prepaid plan. But, no matter where I port her number to, they will be asking for her account number. Where do I find this for her, given that she has a prepaid sim, and from what she can remember, doesn't have any paper work in relation to it. Thanks for any help.