I have Bord Gais but don't pay by direct debit, rather I log in each month and pay by a credit card.
In December there had been website changes, (I was told), and I was presented with double the figure on the bill, and no way to alter it.
(Previously I would have put in myself what amount to be deducted, so could have put less than the amount due).
I phoned up, and tried to pay telephonically by automatic voice (if you follow) but although that first said the correct amount due, it then wanted to deduct double. I had to get an actual person to take the payment, as he could override the amount.