you should call the real Homeland Security office and ask for help.  Tell them what this person said, and I am sure they would like to know they are saying they are homeland security.  Sounds like you are being stalked as well.  There are laws against that.

Man with foreign accent (India maybe) called saying our number had been picked at random for a free wireless home security system. He did not identify his company. Told him we were not a home, but a business and he hung up. Also had the same exact call to one of our company cell phones the day before. Caller ID said unknown name, showing the number 830-200-0422. We never do business with any company that cold calls, they almost always turn out to be a scam.

Unwarranted & unwanted call from 830-200-0422. I will not answer. No message was left.
Thank goodness to all that report so I know NOT to answer!

Called my cell today; let it go to voicemail; of course there was no message.

Called cell, wanted home security