I changed my prepaid to Contract but the number still hasn't moved to the new sim card

Hi, I used to have a prepaid subscription but I changed it to Unlimited expert in a O2 store, the guy in the store told me that he also applied for the change in the mobile number but I still don’t have my number in the new sim card but instead a different one. how much time does it take to migrate the number from my old prepaid sim card to the new with the contract? thanks

Edit by o2_Katja: Moved from prepaid to our english community