Unauthorised payment debits from my account

I made an enquiry because I was interested in Fibre. I was required to enter all my details. They keep sending me sms that my payment was unsuccesful. I DO NOT WANT their service yet my bank account was debited with R249 now. I WANT MY MONEY BACK - this is theft! I AM NOT INTERESTED IN THEM. I have tried calling them umpteenth times but nobody answers