I paid for a vehicle scan that was not used because the car had already been scanned

I paid for a vehicle scan that was not used because the car had already been scanned. CarScan told me to email Paystack for a refund, but Paystack has not responded to my emails. When I contact CarScan again, they say they cannot assist without a Paystack reference number. I have proof of payment but no one is helping me get my refund.