You mean that the message "no SIM" is appearing on the phone when the 48 SIM is installed?
Is the phone unlocked for use on any network?
What make and model of phone is it?
You say that mobile data isn't working but presumably if the phone is saying "no SIM" then you don't even have a connection to the 48 network and calls/texts aren't working either?
If you need to contact 48 support about this then see the links in my signature below.
