How to refresh SIM-card info or clear cache?

I have put a SIM-card into the FP2, that was not yet registered by the provider. It showed “Netz” (Net) as provider and no number. After registration the cards works, phone-calls in and out and data is fine, but the settings still show do not show network/provider and number:

I tried to reboot, took the card out, even replaced it temporarily with another SIM, but it does not help- The FP2 has cached the false infomation.
So how can I get the FP2 to rescan the SIM or clear the cache.

Maybe that’s the info your SIM card sends to the phone. Both of my cards don’t show their number (but an older one did) and my Spanish card shows the name of the German company it uses for roaming.

Might be possible. I never considered this. My other card does shows provider and number, but it is about 10 years old.
Maybe mobile providers nowadays get sold so often, they no longer brand their cards.