Rufmitnahme von O2- Vertrag-sim zu o2-prepaid-sim

Please help me, it is urgent :( !

I had a contract with O2 named unlimited cost 20euro per month
i canceled it two weeks ago, it is scheduled on 22. Juni that end the contract.
I did turn on Portierung (there is a message and an email confirm this, a supporter helped me)

now i buy a new O2 prepaid sim karte, just activate it (not this account)

and i want the old number with me to this new sim card.

but when i put the anbieter : it shows like this below
 

Please help me.

Edit o2_Gerrit 30.06.2026 moved to English O₂ Community: Mobile