doesn' refund and debit m after settling accounts

Last weekend on saturday i settle my account with getbucks,i asked a lady which helped me over the phone to assist me on settling my account with ref no,account no etc ,she then gave me the wrong ref no and i settle someone else's account,she told me that they will arrange refund ,no refund was made yet to date ,then this morning after all my account was settle 4 debit order went off ,i sent the lady an email but no answer ,its really poor service .please advise me on when this will be fixed ?