i want my money NOW!!

i have received a call in March from Vodacom, offering me a deal of 2 phones. after i hung up i realized that everything was *****, how can they offer me phones whereas they declined before. i called back and cancelled the offer immediately, to my surprise at 23;41 the 2nd of June they have debited my account, i don't know how because i did not authorize nor give them my banking. i want my money!!! number is now going through