Regarding Rechnung and Billing

Hello o2 community, 

My Kunden Nummer ist: ******785

Rechnungs Nummer: ********09/06

I would like to ask you a question, I have transferred my old number from winsim to my new o2 Vertrag and it has been successful. However this month in my Rechnung I got charged high than normal? Do I have to terminate my o2 number which was given during the time of the contract as it seems I have been charged for both of the mobile numbers.

Edit o2_Alina: Kundendaten anonymisiert