my monthly Bill is overcharged

Did you actually look at the invoice or just the notification? On page 2 it shows exactly what has been charged. The additional amount is almost certainly the connection charge.

Yes I am talking about the whole invoice page 1 n page 2 the same amount it shows €61.97.

I didn't sign for o2 home internet and the staff didn't told me about any connection price she only confirmed for €30 every month I have to pay and that's why I agreed. I have all the papers which I get from O2 shop in Konlenz.  Can you check my invoice please

Hi @Saeed7 

Welcome to our community.

I assume that bs0 was right and that the increased first invoice is related to the activation fee.

Please check your invoice, the whole thing should look something like this on page 2

Kind regards Matze