Bad experience ever

I have been trying to change my debit date from the 1st to the 25th. You keep saying i should change on the 25 but when i try to change on the 25th you tell me that i should change on my side, i have escalated this that i am not able to change on my side. Now you have switch off my internet after i have escalated it that i will only be able to make payments on the 25th . is not like the is a month that i skipped without making payments. Everything went south after trying to change debit date.