Say they can fix my Internet against hackers

Who claims they are Microsoft who can fix my internet problem.

Its a scam.  My neighbor fell for it.  I found out about a month later when she told me how much faster her computer was running.  I told her about the scam and she took her tower to a computer repair shop.  They discovered that the scammer had turned-off her anti-virus software.  She and her husband spent the rest of the day changing bank account numbers.  They ended up replacing their tower.