Billing date change not set inline with payment date

[#1]

Several months ago we moved billing date from 21st to 15th of the month in line with payday. We now get billing notifications on 15th but Plusnet are still not taking payment until later in the month. This is causing budgeting issues and makes the whole exercise a complete waste of time. Please move payment date forward to the same date as billing (15th monthly)
*Tried using online chat: unavailable
*Tried phoning as website said open until 10pm but your phone-in actually closes at 8
We've been consistently let down by daily internet drop outs since joining plusnet. The customer care appears to be greatly lacking and we have never had a resolution to our issues. Thankfully, we are only a few months away from the end of our 18mth contract, which clearly hasn't been honoured by plusnets service. Looking forward to going back to SKY.
For the love of God, get one thing right and move the payment date accordingly. Cheers

[#2]

I believe if you pay by direct debit there’s an advance notice on a payment which means the money leaves your bank around 5 working days after your bill generates. 

If that’s the case to avoid the advance notice direct debit guarantee, it could be worth changing your payment method to a debit or credit card. 

Another option is to move your bill date with in mind of the direct debit advance notice period. I think you can only change a bill date once every 3 months though.