Ok, so where can I see that the money you changed from me by mistake have been turned back?

@Charged by mistake 

the amount will be credited to your customer account and will be charged with the forthcoming invoices as long as it is spent.

Thanks to @bs0 for details.

Greetings

Once o2 have credited the amount to your account you should see it in the next invoice.

I hope so, because now There is no guarantee that o2 won’t charged me by mistake again

Are you always this negative?

No, there is no guarantee that any contractual partner you have might make a mistake at some point.

This is not a question about my negativity. This is the question of your responsibility to provide your help with a good explanation. If I didn’t go here to ask what was going on and why I had been charged by mistake, maybe nobody would notice that I have been charged. I went to 3 o2 stores and got 3 different explanations on this situation. 
I understand that we are only humans and everyone can make mistakes, but I accept it only when the company gives me the insightful explanation on what happened. 

But that you that now you more or less explain me what happened

But thank you that now you more or less explain me what happened

I have no responsibility at all  in this respect. You appear to mistakenly think that I work for o2. This is a forum where mostly customers help each other.

Nevertheless I am glad you now have the information you wanted.

Oh, sorry in that case. I was a bit angry because I was not ready that o2 overcharge me

Hi @Charged by mistake, 

I fully understand your attitude when the invoice differs from what you expected. 

Is everything clarified with the refund you received? You see the refund in your invoice under the point “Beträge aus dem Vormonat” as “Guthabenbuchung (19%) - 03.11.2021” As you see, you did not have to pay anything this month and the rest will be balanced with your next invoice. 

If you have any further questions, just come back here. 

I hope that in the future, you will make also very good experiences with o2. 

Loving greetings,

Tobias