unauthorised debit from my account

I have never had any dealings with this company (Capital Computer Bureau) and i do not know where did the get my banking details, it is the second time the debit my account without my permission and it is affecting my credit score because i have to reverse the debit orders, when i call i was reffered to ANA who's line is always busy, someone please advise me where to ascalate them, Police,lawyers or what?