I've cancelled my account twice and I'm still being charged

I've moved abroad from Germany in February. Right after, I've notified O2 online and provided the required documents.
O2 cancelled my line, but not my wive's, which is under the same contract. I've sent a new request and provided the required papers again, but nothing happened and I'm still being charged.
I'd like to see it solved right away.

edit o2_Manga: veschoben von o2 Mobilfunk: Vertrag & Tarife zu Englisch: Mobile