Battling to get a refund for travel extras as flight cancelled!!!

I booked a flight through British Airways on the 13thJanuary from Johannesburg to Rovaniemi and my connecting flights from Heathrow to Helsinki and Helsinki to Rovaniemi were with Finnair. The flights were cancelled and we were booked onto alternative flights for the following day with KLM however I had booked and paid for travel extras with both British Airways and Finnair. I have since requested a refund from British airways for my seats that I paid for and have been refunded but when I went online to request a refund with Finnair I get an error stating that I booked through a third party and I should contact them however British Airways says I need to contact Finnair directly. You do not have a local number to call to request my refund so I prefer to do this online and there is no contact form online so I am unable to reach you yet I would like my refund of the 86 euros I paid for my seating on the 2 flights for 2 adults.

My booking reference is Y7NKCL and would appreciate it if this matter can be resolved as I find your process very difficult when it comes to refunds when I was not the one that cancelled the flight.