I'm also affected by the issues Three Prepay customers are facing.
Three don't care enough to even communicate that there's an issue (even though it's been going on for about 10 hours at this stage), so my advice would be to order a new sim from https://gomo.ie/
€14.99/month for everything and reviews look good.
Would advise others to do the same, pretty straight forward and you can keep your number.
Hey @Add_96841, We are aware that some Three prepay customers experienced issues with call, SMS, and data services on Sunday. The issue has now been fully resolved, and we apologize for any inconvenience this may have caused. If you're still unable to use services as normal, please restart your device, and your service should resume. We can confirm that no customer will lose credit due to this issue, and Three is working to ensure that any impacted customers are credited appropriately in the coming days.