No refund for cancelled booking for 9 months

As a foreigner I am writing it in English and I hope this is acceptable. To, Headout (Gladiator Tours), As promised you did not refund the amount of Euro 100 after you cancelled my booking (Booking ID 16208387) on 03 Feb. 2024. You claimed that you have refunded but my bank informed me after follow up with ARN you provided that "In the cardholder documentation there is no compelling evidence such as proof that the merchant cancelled the service and promise to issue a refund to the cardholder." You also did not respond to my request to provide evidence of making refund but you never did. It has been 9 months now and its very disappointing. Hence, I would like to request again to initiate the refund ASAP. Best Regards, Sushil B. Karki