Just enter MIASphere in search on this forum and follow the advice. In particular to set you premium SMS spend to zero.
Thanks for reaching out @Loulou84, to make things a bit easier for you I've copied a response of mine from a similar thread. If you need any extra info, let us know.
We do understand the concern and we've recently made a commitment to cut ties with a number of third party content providers by January 31st. For more info you can check out our blog → https://yescrowd.optus.com.au/t5/Blog/Changes-to-our-Premium-Services-offering/ba-p/351928.
“We’re suspending certain subscription-based Third Party Content providers on all mobile services that use the Optus network (except Virgin Mobile Australia customers)."
For the moment, we'd suggest jumping onto live chat → www.optus.com.au/livechat/pmobi. You'd need to ask the consultant to action the following for you.
I understand that you've given it a go but we'd really need you try again. If you need us to follow up on your refund, message us back here and we'll gladly help out. They are available 24/7 so maybe try in the early morning or late evening.