About two weeks ago, letters started landing at the Envision Credit Union head office in 91原创.

They'd been marked "return to sender" by suspicious recipients, all of them U.S. residents who were quite right to doubt their veracity.

For one thing, the address of the Envision Financial Regional Office had the wrong postal code -- V2Y 2X2.

For another, the credit union has nothing to do with any American lottery.

"Congratulations" the letter read.

It claimed the target had won last year's surplus of the Michigan Electronic Millionaire Raffle.

Some mailings even came with a cheque.

The letter instructed the recipient to call a 鈥渃laim's agent鈥� before cashing the cheque.

However, the number provided was that of a fraudster who will collect a fee and claim the cheque is legitimate when it isn't.

The credit union has posted a warning on its website for any Americans who Google Envision because of the letters.

"If you receive one of these mailing do not cash the cheque and contact your local law enforcement agency immediately" it reads.

"We've never had anything like this" said Envision spokesperson Sarah Pederson.

Envision has also posted a page of anti-fraud tips at: