contact to fix the uncorrect fees

Hello, I want some assistance regarding a situation. I can’t call because I am abroad. I paid my bills before the warning deadline and I called to assure that and the lady said it was fine. but I still got the 15€ collection cost fees to pay this month. Can you help please? 

Can I get an email to contact someone with all my information to get this fixed? I can’t contact anyone I tried everything.