I was with VM mobile for 18 months. My phone is\was always on 24\7 & never on silent. Not once did I receive a txt from VM after 9pm and never before 8am. If woken I too have trouble getting back to sleep and if you knew this would be an issue for yourself then the only viable option is to change your phone profile to silent or switch it off.
I am sure VM do not set out on some sadistic vendetta to wake up everyone at 2am if payment has not been made and I have never heard of a company cutting off services on the date of a due bill especially over a bank holiday unless that person was a persistent non\late-payer.
My 2 txt's worth of input