Early cancellation of DSL contract because of relocation in another country

Hello O2,

Unfortunately I will have to leave Germany and I will have to cancel my DSL contract with O2. It is a 24 month contract. As far as I know, in order to cancel the contract I have to send a letter requesting the cancellation. This letter must specify the date I would like the contract to end and I must also agree to pay the three month basic fee for early cancellation. In addition I must also send the following documents:

• Deregistration (Abmeldung)
• Proof of tenancy agreement in the other country.

Finally I will also have to send back the router given to me by O2.

My question is: Is there something that I am missing?

I would also like to verify the address to which I must submit my cancellation request, and if different, the address to which I must send the router.

Thank you very much for your help.