Hilf mir zu verstehen, warum es so hoch ist, weil dies meine erste Rechnung ist

Schaue in deinen Einzelverbindungsnachweis, dort stehen die Verbindungen. Wahrscheinlich Anrufe ins Ausland.

 I had no idea that international calls are charged, i believed like with lebara it also had mintues free. I just saw and there were major calls, can i call them to get bill reduced also nobody told me about to not make international call

​@Manish_Rathore 

Sorry, but it clearly states in your contract details that international calls are charged. And o2 will not reduce the bill.