WESLACO - A Rio Grande Valley man lost hundreds of dollars, and had his computer taken over, all by calling a number on his screen.

We heard of people posing as social security representatives and even police chiefs.

Now, hackers were able to access Melvin Lievsch's computer and forced him to buy a service.

"I don’t know I just had the computer on and all of a sudden the whole screen comes up. You got to call this number,” he says.

He says he also had his printer on when suddenly stacks of papers that looked like a contract were printed out.

He was then advised to call their toll free number.

"I did what they told me to do and even asked for a credit card number, and what's they got, it was too late for anything," says Lievsch.

He says he lost close to $400.

CHANNEL 5 NEWS called the numbers the contract provided.

When we asked about what kind of company they are, they hung up.

Chief Engineer, Michael Leal, explains these hackers can get into your computer by using pop ads or links.

Leal explains a company will not contact you.

"You'll never be solicited to have your own computer fixed. There's no means of a company knowing that your computer has been infected unless they were the ones that infected it," he says.

Lievsch says he learned a lesson.

For more information watch the video above.