Debited in the incorrect date

Home choiceis the worst company one can deal with two months ago they debited my account before the debit date I asked them to do a refund they did the refund twice in error. I complained about it to date no feedback last month they advised my account is in arrears so I tried paying the amount off even though it was an error from their side. I logged into my account checked the due amount I paid more then that few days later I logged in another amount due how is that possible, I call their contact centre I'm being transfered from pillar to post. They affecting my credit record negatively