Lewis furniture bank account access

Agreed to lewis furniture stores to debit my bank account but this month they decide to take money from my bank twice and its even difrent amounts, I agreed n signed that they take the money out the 1st of each month which they also didnt do last month they decided on they're own to take it on the 30th ,luckily I had money on that day for them to deduct,this month they decided to take it on the 21st I even loged a complaint on it and then a week later the 28th they deduct again, so my advice to people out there don't allow lewis furniture stores access to your bank account, because when u take them on about it they keep referring you to someone else and those persons I was referred to all says they will look into it,not carring about the mistake they made and that the money taken might have been for something real important