Help or Advice on receiving a bill for a prepayment meter with Scottish Power

Divin

Hi
I have had my prepayment meter for 27 years.  It was in my house before I bought it.  I know it is cheaper to pay monthly but I have found I prefer to use the prepayment method.  
Anyway, I have never had a problem with this method but today I have received a bill for a request for payment of £704.  I have never been in debt, I have always topped it up but for some reason today it says I haven't used my prepayment key in a while and they are worried I might have a problem.  I have been using it.  I have been using the government top up of £66.  And when this runs low I have had to put an additional £40 to £50 on extra each month.  
Can anyone help or advise what I should do.  I cannot contact them until Monday.  I don't know how I could owe this money when I prepay for my electricity.
Very worried about this and any help welcome.

Gerry1

Could be an Erroneous Transfer, which would mean that your payments have been going to another supplier?

Check Find My Electricity Supplier.

MikeyPGT

Scottish Power are a bunch of shysters - good luck with trying to get hold of them as their phone and emails systems are beyond useless.  I would take it up though www.resolver.co.uk as it seems to be the only way to get a response from Scottish Power.  

macman

What are the details of the bill?

markin

This isn't the first thread on this happening, hope its not the start of a flood of threads.