Spend Cap \ Block Premium calls & texts

Hello,
I've just moved myself and family from O2 to Lebara. With the kids accounts I was able to set a spend cap of £0.00 which meant they could'nt use premium rate services. Is it possible to set something like this up on Lebara?

By default spend cap is £0 unless you turn on auto top up. The Lebara contract is technically hybrid pay as you go but you can enable auto top up which makes it act like a contract.