More than £30,000 has been scammed from people in the Magherafelt area in the past week, according to the PSNI.
In a Facebook post Magherafelt PSNI appeal to the public to be careful and protect their hard earned money.
"We know the scammers are the complete dregs of humanity, thats a given, and they generally operate from the other side of the globe, again well established fact," the post reads.
"These days its an unrelenting tide of fake emails, dodgy phone calls, false claims of help etc, you know the drill.
"It is immensely frustrating for us to see good people time and time again having their lives ruined by scammers.
"So we can issue all the warnings in the world, highlight every scam going but the bottom line is you are the only person who can 100% stop it. Yes you.
"When that thief phones or emails, you are the last line of defence, you need to be on your A game all the time. These leeches are experts in mind games and follow a ruthless plan.
"PUT THE PHONE DOWN
"By even speaking briefly to these people your name goes on more scam lists.
"BT aren’t calling about the phone.
"Your bank hasn’t noticed unusual activity on your account.
"Microsoft don’t want to fix your computer.
"Your internet provider has not detected a fault.
"HMRC aren’t looking to refund/jail you.
"No one is phoning to warn you you are being scammed.
"You ARE being scammed."