How to get billingsupport

1/6/26 placed an order to change channel services. Yesterday the billing department stated they saw the order, but the rep forgot to complete it. Billing rep completed the order and backdated it to 1/6. I have an email stating the order was issued dated 1/6. I am owed a credit from 1/6 to yesterday. The rep said she could process a credit from 1/6-1/10, but her limit is $30. I asked about the rest of the credit and she opened a "case" for the Finance department to review. To I received a stock email only saying my credit request was denied. No other information. Where do I go from here?