Surf Day Flat

I have a problem with my number. In mid of December, O2 activated the surf day itself then when I paid again for my the 15€ for my number in 29/12, it kept taking from the 15 euros as a (surf day) and the wifi was not even working. Now it says that my prepaid limit it all used up.

how can I solve this issue and why would I pay again if I only pay every month 15€?!!! It should stop taking money from me as a surf dayflat!. 
It even activates the surf day flat saying that my phone is connected to their internet when i’m NOT

Edit o2_Vivian 07.01.2023/11:02 Uhr: von Surf-Dayflat abgetrennt und zu Englisch o2 Community Mobile verschoben