Do you mean that the phone is sporadically losing the connection to the 48 network altogether (i.e. no signal bars) or that just mobile data is the problem?
What exactly happens when the problem occurs?
When was it working ok last?
Are your APN settings configured correctly?
Have you tried reseating your SIM in case that makes any difference?
You might want to try a replacement SIM in case that helps.
If you need to contact 48 support about this then see the links in my signature below.
