Kündigung

Hi O2, my german is not good so I write u on english, I want to terminate contract and I did this “Kündigungsvormerkung” and here says that I have to call in next 10 days, as I said my german is not that good to talk, is it possible  to just terminate it without phone call ?
Auftragsnummer : 6******5

Interne nummer : 5********4

Handynummer: 0176 6*****5 

Thanks in advance.. !

edit stefanniehaus: Persönliche Daten entfernt

Edit o2_Larissa: transfer to English o2 Community: Mobile