Under industry standards its the norm for final bills to be produced up to 6 weeks after leaving a supplier.
Once the final bill has been produced then factor in the payment process.
I would guess you have left the DD live on your bank account so that any balances can be settled?
If you have closed your DD then you will need to contact PP direct via the APP and if your final bill has not been emailed within 6 weeks.
Hope this assists