You cannot cancel in this forum as this forum is a customers-help-customers forum.
You'll need to send your cancellation request using any of the official contact ways - meaning by mail or by contact form while being signed in - to Vodafone.
Please note that your request has to be submitted in German language as German is sole contractual language - requests in English might get rejected.
Next thing is that you are still bound to your contractual term -AND- that your request has to be submitted before the notice period ends - which is usually either 3 months for contracts with an initial contractual term of 24 months -or- 6 weeks for contracts with an initial contractual term of 12 months.
