@KazoInternetUser You can only renew your contract over the hotline or here over an o2 moderator. I strongly recommend the way here over the community with the assistance from an o2 moderator. You get an offer over email that you must approve. 
You will get also a discount because you have a 24 month contract. Please wait some days for get an offer. 
Best regards and have a nice weekend.

Okay, I will wait for an offer here. Thank you.

Hi @KazoInternetUser 

welcome to our community. 

Thanks to @Joe Doe for giving some advice.

I sent you an offer by email containing your desired tariff and the rent for the existing router. If you prefer to waive the fee for the router you can ship the device free of charge back to us and purchase your own one. 

According to the Transparency Regulation, I am obliged to refer to our product information sheets (can be downloaded) 

There you will find all product details listed again.

If you agree to the offer just click “Vertrag verlängern” and everything will be done.

Greetings

I accepted the offer. Thank you for your help.

@KazoInternetUser You are welcome. 

It was a pleasure for us to help you.

Don’t hesitate to contact us if you need further assistance.

Best Regards Matze