Für DSL gibt es einen separaten Account, den Du evtl. nicht angelegt hast. 

Kündigungen erfordern grundsätzlich die Form als TEXT, d.h. Brief, Fax, etc.

WhatsApp oder Chat scheitert evtl. an der Authentifizierung als Kunde, insbesondere wenn Du keinen Account angelegt hast und Deine Kundenkennzahl nicht kennst. Brief scheint ohnehin empfehlenswert, da Du Deine Abmeldebescheinigung beifügen musst - je nach Vertragslaufzeit bei DSL. 

If you have further questions -feel free to ask in english to avoid misunderstandings!

Thanks for the answer 

Than to be clear 

A letter asking to cancel with my client number would be enough? To which address?

Correct, client number or phone number. If in doubt 

Telefónica Germany GmbH & Co. OHG
Georg-Brauchle-Ring 50
80992 München
Deutschland

better is in principle the adress on your bill (Nuernberg)

Don´t forget the “Abmeldebescheinigung” from your old city in Germany. You have to pay 1-4 month due to national law for DSL. 

I got the Abmeldebescheinigung but when I tried to access my bill in the email that they send me 
they send me to my webpage that only have my cellphone information but not the DSL 
If I send the letter to nuemberg it will be ok?

correct!

btw - for DSL and mobile phone you should have separate accounts. 

Hello @Moreoneannoyed and welcome to our o2 community :-)

I transfered your thread to the english community and changed the topix so other people will easier find this if they have the same question.

As far as I can see @Klaus_VoIP already answered your question, correct? Is there anything else that we can help you with? :-)

Regards,

Lars

I cancel my account on 28/1

and I understand that I had to pay more 4 months, but this mount I receive a bill of 63,24 normally is 39.

 without any explanation or clarification why 
Why did this happen? 

maybe a rental router  - charged due to missing return?

Hello @Moreoneannoyed,

like @Klaus_VoIP i´m also thinking, thats the not returned router which is charged on your invoice. Do you send it back?

Kind regards,

Larissa

I dont live in the house anymore. and the router was in the house before I move in and was the same after I left

nevertheless - you must fulfill contract requirements - means you must send back the router

Hello @Moreoneannoyed ,

@Klaus_VoIP described it correctly - the device has to be returned.

Since you´ve left not just the city: The chances of getting in touch with current residents are rather slim to non.-existent, correct?

Viele Grüße,
Kurt