lankeela, do you mean the £5 emergency credit? If so, yeah, my mate was always in emergency - always trying to catch up. I've forgotten how many times he thought he still had the emergency credit when he didn't. He was so 'tight' he used to unplug everything, and I mean everything, when he was down to his last 50p. I used to sneak into his house with his spare key, steal his meter key and put £50 on the electric. I never bothered with the gas as they were so far in debt, due to the standing charges, I just left that for his mum to sort out.
I haven't seen or had anything to do with prepayment meters for a couple of years so I suspect they have changed how they work and how the emergency credit works.
If it works for you, then that's great :)