lot are doing charger back on illegally casinos,(without UKGC licence), most of Illegally casino charger you card as retail shop in Nigeria, Mexico and Azerbaijan (laundered money) , so Visa or Mastercard they dont know you pay Casino.
P.S you can check casinomeister forum, also ombudsman can help for free
I use to love Casino Calzone lol
Soon UKGC will come out with new Rules a lot of UK players with go to Crypto casino