Unauthorized Debit Order

I am very disappointed with this company after I have allowed them to settle my account by debit order. 1 Month after they debited the settlement amount they sent me an sms saying that another debit order will go off the following day. I reacted and informed them of this mistake immediately and to stop this unauthorized debit order before it happens. And surely to no surprise the debit order wasn't stopped and I now have to waste my time trying to reverse and get my money back.. How long will this fight be!