Anschlusspreis Option AVM FritzBox?

Hello,

I have two mobile phone contracts with o2 and recently also a Cable connection, for the cable connection, firstly I didn’t rent the router with the cable contract, but after a few days, I called the customer service and said I want rent the router. 

However, this month I got the invoice that I'm being charged 49,99 for Anschlusspreis Option AVM FritzBox - 19.05.2022. I have already paid the “one time connection price” for 69,99 euro last month, and the "connection price of the router" doesn't make any sense for me. Then I checked the price from O2 official site and see how much for ordering Cable connection with router, it never mention the connection price of the router even the one time connection price decreased from 69,99 to 34,99 euro.

So, I sincerely hope that I will be offered some kind of compensation or explanation.