Unauthorised Debit on my account

I have received an unauthorised debit on my account from this company that I know nothing of. I have not signed up with your company, so how can you debit my account? I probably won't get a response back regarding this as I see you only respond to reviews with a 5 star rating. So I'm not holding my breath with that. Should you continue to debit my account, I will take it further.