Duke Energy complaint: billing

Duke threatened to turn off my power if my bill was not paid in 30 minutes. I paid the bill in question on 13122 (16 days ago). They said they are no longer accepting mailed payments and that my money was being refunded to me. Yet if I go on their web site it says pay by phone, mail, automatic payment, bill payer through my bank or by internet. They also told me that they would not accept payment over the phone. When I went online to pay my bill is now $104.78 more plus a convenience fee of $1.50 to pay online. I was never notified of this and I do not want to pay $1.50 to pay online because they can’t process a mailed payment. And by the way, they have the correct billing address but are mailing the bill to the wrong address. I have contacted them twice and noted it on the payment receipt multiple times since May of 2020.