Flexicell
Unautherised debit orde

Hello Peter
I just received an sms from my bank to asked whether I have authorised a debit order for R99 to Flexicell. I have no account with Flexicell nor have I authorised any deduction from my account. My question is: How can any company deduct money from a personal account without the necessary authorisation?
What should I do to get my money reimbursed?
Faika