No matter which telephone company provides your service, you may soon get a letter claiming you’ve won Verizon’s $750,000 sweepstakes, accompanied by a $4,500 check.

Sorry to break the bad news, but you didn’t win anything. Verizon has issued a warning that the letters, checks and sweepstakes are all phony. This scheme is just one of the many ways in which scammers falsely use the names of reputable corporations to try to dupe people.

“In this case, some goons feel it’s fun to try to take advantage of unwitting victims,” Verizon spokesman Bill Kula tells Scam Alert. He adds that other companies besides Verizon are involved in these scams.

The Verizon sweepstakes is the latest spin on a common check-forwarding scam. Posing as a reputable firm, the scammer sends you a check and asks you to forward part of the funds, usually to another country. In this case, the $4,500 check purportedly covers $3,200 in processing fees. The letter directs you to pay the fee via MoneyGram in order to claim the jackpot.

In reality, the check is not worth the paper it’s printed on, and you will lose any money you send to “fee agent” Mary Taylor in Toronto, Canada; your bank will hold you responsible for it. In addition, the scammer may try to solicit personal information from you to use for identity theft.

Like most unsolicited prize notifications, the letter and check hold valuable clues to smoke out a scam. Here’s how to do a little online detective work and protect yourself:

Check the address. Scammers occasionally use authentic company addresses, but more often they list fake ones. In this case, the letter and check appear to have been sent from a post office box in Washington, D.C., which is difficult to authenticate. But a quick Google search using the keywords “Zip Code” and “20914” (the Zip Code printed on the documents) brings up several websites showing that 20914 is in Maryland, not D.C.

Pinpoint the area code. A simple Google search of a telephone number can identify its general location. The phone number listed on the bogus Verizon letter starts with 011—the access code to call outside the United States—followed by a prefix for Ireland. But the fee agent was supposed to be in Canada, not Ireland.

Resist the urge to call. Playing cat-and-mouse with scammers can prove costly. Anyone calling from a U.S. phone will be hit with expensive overseas calling charges, and scammers often place “winners” on hold, perhaps to confer with each other about milking you dry. Talking with a scammer could lead you to reveal more information about yourself than is wise.

Count the (routing) numbers. Every legitimate check has a nine-digit bank routing number, usually in the lower left corner, identifying the financial institution that holds the account. The fake Verizon check, however, has a seven-digit number—a dead giveaway the check is bogus.

Again, online sleuthing is easy. Simply type “bank routing numbers” in an Internet search engine for links to several websites that allow you to type a check’s routing number to find out which bank is paying the funds.

This is an important step, because it could take up to two weeks for your bank to discover the check you deposited was fraudulent. Scammers depend on a quick deposit followed by an immediate overseas wire transfer to make their ploys successful.

Watch for scammer grammar. The Verizon notification letter and check are fraught with spelling and punctuation errors, missing words and odd abbreviations, such as TELL for telephone, instead of the American-used TEL. Such idiosyncracies suggest the documents were produced by foreigners, not U.S. corporate officials. That’s not to say a well-written letter is necessarily authentic, but one riddled with basic errors is certainly phony.

Get real. Telephone companies and other service providers rarely, if ever, hold big-money sweepstakes. If they did, American-based firms would be likely to advertise such contests prominently on their corporate websites. The biggest clue of all? No legitimate sweepstakes ever requires winners to pay processing, insurance or other fees. Whenever you’re asked to pay to win, you’re being set up to pay dearly.

The Federal Trade Commission and the U.S. Postal Inspection Service offer more information on sweepstakes scams and how to avoid them.

Sid Kirchheimer is th author of AARP Books/Sterling’s Scam Proof Your Life.