Oakhurst unauthorised debit orders

Many unauthorized debit orders detected on my account with the reference OAKHURST. I called and the search with my ID and told I am not a client.. Well, this I knew... But my question is... Why are you debiting me... For what service or product are u debiting me and where did you get my bank details. Im yet to have an answer.. 0836526606 I need an urgent call back.