I need to change my internet billing date? Every time I click on the change date it says something went wrong.

I need to change my internet service due date for autopay from the 24th to the 10th. I have spoken to your department and they say can not do or some lie and say i will send it to the right team do change this. i have tried to change on the app or online and it says something went wrong. So then I turn off the autopay and then click back to set up again the autopay and still when i click on change date it says something went wrong. I think this is something on the backend. Can you please fix this or change my due date for me. Also I do have complaints on previous customer service agents lying to me on this. And the last supervisor would not do anything on this. He said they do not have an IT department to submit tickets on this. Your outsource agents are useless.