Need help with payment arrangment

Due to some unforeseen financial challenges, I am unable to pay the past due amount I owe for a payment arrangement due in 3 days. I was able to make a smaller good faith payment and can make one additional smaller payment. In order to pay the full past amount due, I need it extended to the 27th. I have tried using the automated system and have been told my account is eligible for a payment arrangement, but the available dates and amounts do not show. I have spoken to two customer service agents and a supervisor by chat. I was told to go to the Xfinity store to request an installment plan. Then I was told that I did not qualify for the installment plan. I was told that I also did not qualify for any additional extension through the billing department but to call the payment department and if they took my call, they might have options. I am just trying to sort this out and not lose my services. I have been a customer for 18 years for multiple services. Any help is appreciated.