Fnb card used for puch**** in mexico

My Card Have been used for online puchase in Mexico I want fnb to give me answers on how is that heppen as I stay in south africa and I also want my money back When I woke up this morning I checked on my fnb account using app and I realize that there was a lot of transactions of didfood I want my money back ...and I also want to know how my card was used without my authorization