FlyOne Ticket Cancellation Failed Despite Refund Guarantee

On August 14, I purchased a FlyOne ticket through the Enuygun platform for a flight scheduled on August 18, under reservation number N46PTF. The total amount charged to my credit card was $91. I relied on the fact that the ticket had a refund guarantee and believed I would not face any issues if I needed to cancel it.
However, when I clicked the cancellation option in the FlyOne application, I encountered a “Booking error” message caused by the Enuygun platform, and I was unable to complete the cancellation process.
After this issue occurred, I contacted Enuygun customer service. However, they only told me that the cancellation could not be processed and did not offer any solution. They also said they would call me back, but no one returned my call. I have a screenshot and system record showing that my ticket was refund-guaranteed.
This is the first time I have experienced such a problem, and I want my inconvenience to be resolved. I request that my flight be canceled and that the full $91 I paid be refunded to my credit card.