You should have ordered a replacement not a new SIM.
A new SIM when activated will not be linked to your existing account, membership, number etc.
That may be the problem here?
This is where you order a NEW SIM:
And this is where you order a REPLACEMENT SIM:
If you ordered a new SIM and activated it as a new SIM then contact 48 support and ask them if they can link it to your existing account, membership, number etc.
Hope this helps.