DOUBLE DEDUCT

I have been having problems with this Challenor something whereby they keep double deducting me. In February 2016 they double deducted me and refunded me but not the finance charges. Then in March 2016 they double deducted me on the 23 March 2016 and again on 24 March 2016. I have bills that I need to settle on the 31 March 2016 and this will not be possible because of them. I want the money they deducted on the 24 to be paid to my bank account by today.