You mean a SIM that was working in phone A won't work in phone B?
Does the SIM still work in phone A?
Are you sure that phone B is unlocked for use on any network?
Won't let you log into what?
What is the "Ed app"?
What internet allowance are you referring to?
Did you buy a new membership or internet addon recently?
If necessary contact 48 support - see the link in my signature below.
Hope this helps.