There is no government grant, no money, nothing will be deposited into your account and nothing legit in that call.
That call was from one of the scammer's fake name and has demanded you pay for made up fees, in cash, via Western Union, moneygram or Green Dot moneypak card.
A Green Dot moneypak card is like sending cash. The minute you send the code off the card, the scammer will drain the card of all your cash and disappear. Once your money is emptied off the card, it is gone forever. Green Dot will NOT refund your money once you discover you were scammed.
Now that you have responded to a scammer, you are on his 'potential sucker' list, he will try again to separate you from your cash. He will send you more emails from his other free email addresses using another of his fake names with all kinds of stories of being the perfect buyer, great jobs, lottery winnings, millions in the bank and desperate, lonely, sexy singles. He will sell your email address to all his scamming buddies who will also send you dozens of fake emails all with the exact same goal, you sending them your cash via Western Union or moneygram.
You could post up the email address and the emails themselves that the scammer is using, it will help make your post more googlable for other suspicious potential victims to find when looking for information.
Do you know how to check the header of a received email? If not, you could google for information. Being able to read the header to determine the geographic location an email originated from will help you weed out the most obvious scams and scammers. Then delete and block that scammer. Don't bother to tell him that you know he is a scammer, it isn't worth your effort. He has one job in life, convincing victims to send him their hard-earned cash.
Whenever suspicious or just plain curious, google everything, website addresses, names used, companies mentioned, phone numbers given, all email addresses, even sentences from the emails as you might be unpleasantly surprised at what you find already posted online. You can also post/ask here and every scam-warner-anti-fraud-busting site you can find before taking a chance and losing money to a scammer.
6 "Rules to follow" to avoid most fake jobs:
1) Job asks you to use your personal bank/paypal account and/or open a new one.
2) Job asks you to print/mail/cash a check or money order.
3) Job asks you to use Western Union or moneygram in any capacity.
4) Job asks you to accept packages and re-ship them on to anyone.
5) Job asks you to pay visas, travel fees via Western Union or moneygram.
6) Job asks you to sign up for a credit reporting or identity verification site.
If you google "Western Union government scam", "Grant green dot card payment scam", "fake grant payment fraud" or something similar you will find hundreds of posts from victims and near victims of this type of scam.