DSL wrong bill

I have o2 DSL XS Flex and I bought HomeBox 2 option as well. At the beginning, I got contract letter. It says that I have to pay monthly fee as 9.99 EUR for 6 months and one-time fee 59.98 EUR for HomeBox2. But now after 1 month, I got the bill. And it has some additional price which says "Einmaliger Anschlusspreis O2 DSL". According to translation, it is connection fee but I was never told about this fee. And even contract letter does not have this fee. Then why do they add this fee in bill? I also confirmed if there is any extra fee at the time of making contract. The operator told that the connection fee is not applied for my address. How should I resolve this matter?