regarding monthly payment

Check page 2 of your invoice; there you can see the breakdown of the amount.

Hey ​@m.mathewliya,

Welcome to our o2 Community. :) 

Getting a higher bill is never a pleasant surprise. Have you taken a closer look at your bill yet? Here you can find a lot of information about invoices and how to access them: o2 Rechnung online einsehen und Zahlungen verwalten

 Is everything working out? ​@m.mathewliya 😊Feel free to let us know if you have more questions.