O2 online order

Hello!

I ordered an O2 sim only Free M contract today and received the confirmed order number. Now I have changed my mind on getting a device along with the contract. I did contact O2 via mail that I want to cancel it but they have not responded. The sim has not yet been shipped. How do I proceed with this? Should I wait for them to reply or order a new device and sim contract?

(Moved to our english community, o2 Michi)