Blameshifting on refund not done

My account was in arrears for 1 month. I made arrangements for the amount to be deducted in 2 payments ns and received acknowledgement. They however deducted main amount two times plus arrear amount. I was requested to send bank statements and promised refund in 5 days. However after 5 days i called and nothing has been done and they are blameshifting. Now have to wait another 3 days making total days more than 10 days