The FBI shares fraud prevention tips as part of a recent bulletin when users are falsely contacted in unusual ways by technical companies, banks, delivery companies, retail, etc., in an attempt to trick & defraud 

https://www.ic3.gov/media/2018/180328.aspx

Suggestions for Protection

1. Remember that legitimate customer, security, or tech support companies will not initiate unsolicited contact with individuals.
2. Install ad-blocking software that eliminates or reduces pop-ups and malvertising (online advertising to spread malware).
3. Be cautious of customer support numbers obtained via open source searching. Phone numbers listed in a “sponsored” results section are likely boosted as a result of Search Engine Advertising.
4. Recognize fraudulent attempts and cease all communication with the criminal.
5. Resist the pressure to act quickly. Criminals will urge the victim to act fast to protect their device. The criminals create a sense of urgency to produce fear and lure the victim into immediate action.
6. Do not give unknown, unverified persons remote access to devices or accounts.
7. Ensure all computer anti-virus, security, and malware protection is up to date. Some victims report their anti-virus software provided warnings prior to attempt.

If you are a Victim

1. Individuals who receive a pop-up or locked screen, should shut down the device immediately. Ignore any pop-ups instructing to not power off or restart the computer. Victims who reported shutting down the device and waiting a short time to restart usually find the pop-up or screen lock has disappeared.
2. Do not re-contact fraudulent tech scam companies. Expect additional fraudulent calls as these companies often share their customer database information.
3. Should a criminal gain access to a device or an account, individuals should take precautions to protect their identity. Immediately contact financial institutions to place protection on accounts as well as change passwords and actively monitor accounts and personal information for suspicious activity.