Baggage Dubbele betaling

Dear, I was promised 15 kg checked baggage by Gotogate for flight BX123 while at the airport (Air Busan) that information was not updated in their system. I was charged again for 14 kg... I have communicated this several times through customer service but I get no help... It seems logical that there is a refund provided for further positive cooperation. (In the attachment you find the payment proof) Thanks for your help. David Booking reference 8142882