This company called and said they were from the Government Grants department and then hung up. The person had a very heavy Indian accent. When I tried to call the number back it was busy.

got a call from this number but was unable to answer. Did not leave any message to my answering machine

person called met in South Africa wanting me to buy stock.
I told him to go [***] his mother.

Got a call from 2013738356 today at 10:22 Am South African time
is there a way to stop them from scamming?

I got an unsolicited call from this number this morning at 08:30, in South Africa.
The caller was a man with an Indian accent. He claimed to be from "Mackie Research" and asked if I knew anything about "Share Markets" (an unusual, generic term - VERY suspicious).
He claimed that they have an office in Johannesburg, South Africa.
He stated something to the effect that the market has done well, and the offer a service where they send you market tips 3 times a year, and would it be OK for them to call me back.
He asked for my e-mail address so he could send me information. I agreed so I could learn more about this SCAM. 1 minute later I received a blank e-mail with the subject "t". VERY suspicious. I flagged it as phishing.
He asked for my occupation and whether, if I was given a tip in the next few months, I would have 10,000 Dollars (presumably USD) to invest. Why would he use this currency if I am based in South Africa? I told him it was "unlikely".

THIS IS OBVIOUSLY A SCAM!!