@Tobystopps Please take a look at these links: https://community.o2.co.uk/t5/How-to-Guides/Have-you-fallen-for-or-been-conned-into-a-premium-rate-s...
You also need to contact O2 and ask them to place the following bars on your account
Bar all Direct to bill debits
Bar Premium rate numbers
You should also ask for a "charge to mobile" bar