National Grid is warning customers about more phone scams.
They call customers claiming to be a representative of National Grid threatening to shut off service if you don't hand over your bank account information.
The callers tell the customers there's a past due balance on their accounts.
They used to only request payment on prepaid debit cards, but their operation has gotten more sophisticated.
David Graves of National Grid says the prepaid cards should raise a red flag.
"We don't ever use prepaid debit cards so that's a good signal right there if someone demands one of these green dot cards or whatever they're called then that's a good signal that this is not a real call from national grid your being scammed.”
Graves says these scammers are likely working from out of the country, which is why it's been so hard to trace them.
The scammers target customers in a cycle, usually after the winter months, when people may have large overdue balances.
While National Grid does call customers about overdue balances but they never threaten to shut off service that day if payment is not received.