The delivery time for a replacement card is a maximum of 7 days. The card has probably been lost or could not be delivered to you and was returned to o2. Did you already checked  your contact details in Mein o2?
There is an English speaking hotline, but not yet for O2 prepaid customers. If you can log into my o2 with your o2 prepaid mobile number, then you can also use the o2 customer chat. Maybe someone can help you to write German in the chat. www.o2.de/chat
 
If you want to conclude a postpaid contract and want to transfer your mobile phone number from the o2 prepaid card to the new o2 contract, then you do not need to wait for the replacement card. Porting can also be commissioned in this way and can also be ported later.

Hi Many thanks for your reply, I checked Mein o2 and the address is correct! In this case shouldn’t I be receiving the money back?

I will try to connect with the chat. Would you recommend ordering an another replacement one?

Thanks

Get the money refunded. Or wait here for help from O2.
After porting the prepaid SIM card will be deactivated anyway. Therefore, you can save the money.

Hello @Helin_U, welcome to our o2 community :-)

I am sorry to hear there seem to be issues with the delivery of your new SIM card. Were you already able to contact our colleagues via chat as already proposed? :-)

Regards,

Lars

Hi thanks for your reply, I have not been able to contact them, through chat. Is there anything I could do to be able to get help from the community support team?

-best

Hello @Helin_U,

we arrranged a refund for the cost of the replacement SIM: I recommend to order a new one via the our mobile app.

Of course you also have the possibilty to sign a postpaid contract with us, maybe one of our tariffs is the right one for you? :-)

You can import your prepaid number either in the order process or after activating the SIM, any existing credit will be moved from your prepaid contract to your new postpaid one :-)

regards,

Lars