Denied Boarding Despite Valid Visas at Skyscanner Flight

I had a flight with Wizz Air on March 1, 2024, at 22:05 to New York Stewart Airport via London and Iceland with my son. I purchased the ticket from a company called Mytrip through Skyscanner. However, the airline staff refused to let me and my son board the flight, citing the lack of transit visas. Yet, according to the UK Consulate's website, individuals with visas for the US, Canada, or Australia are exempt from transit visas. Additionally, we were supposed to transfer to the same airport without going through security. Shocked by the incident, I sought a refund for our tickets, but I couldn't reach Mytrip. I suspect it was due to the weekend. I demand a refund for the ticket fees.