I found a post elsewhere on this site that fixed it up for me!! Pasting below
Make sure that your APN settings are configured correctly.
Text "APN" to 50048 and follow the instructions:
https://community.48.ie/t5/The-Newsroom/APN-Settings-step-by-step-guide-for-50048/td-p/60689If that doesn't help then you'll probably have to contact 48 support for further assistance.
See the link in my signature below or email them at support@48months.zendesk.com
I am not a 48 employee - if you need to contact 48 support you can do so by chat, email (support@48months.zendesk.com) or phone.