Overcharged for extra luggage - slow response time.

I arrived at OR Thambo on the day of the flight, the 17th December and my luggage was over weight.. I accepted that I needed to pay for the extra kilos and asked the check in attendant if I could pay for this via the air Seychelles App, which she responded I could. I proceeded to pay and after three times managed to pay for this via the App.., but realized it had accepted payment for the return leg, which could not be interchangeable for the onward leg. I then asked the attendant what to do and she told me I needed to pay for it at the airport again at the higher prices. I proceeded to the counter to pay for the extra kilos again at a different attendant that couldn’t understand the process and took 30 mins to process this after numerous attempts. I then asked them what I should do with the incorrect payment made earlier and was told to complain to the airline, as they couldn’t help me. I sent an email on the air Seychelles website contact email address and have not even received an acknowledgment of receipt of this mail. I received a mail from Air Seychelles asking for feedback on my experience and proceeded to highlight my experience and disapproval and have still not received any feedback from them. Very disappointing that they’re quick to take our money and very slow to even respond to any query.