********* behaviour

They called me to notify me that i have arrears on my account we arranged a once off debit order over the phone ,we agreed on one debit order for January ,but they kept debiting my account ,when i asked for my refund they told me i gave them the mandate ,i asked for a recording because i know its not true i never said i need a monthly debit order ,i asked for a recording they refused ,I am very dissapointed with this ********* behaviour and lies ,I really don't know who can hold them accountable because they ruined my life since one of my debit oders bounced because the took money that was meant for it.