Calls, can hear sounds in the background, then they hang up. This happened severaltimes.
I called back, they pick-up, say mothing, then hang-up.
Tried calling serval times, now I am getting a message saying the number is temporarily disconnected.

A Google search of their number shows their website as http://advancedproteks.com/prosaver.aspx

Can hear background noise, then they hang up.

This guy is a crook.  We bought some fuel treatment from him.  He sent some and didn't work.  We tried to cancel but he sent more.  Had to cancel credit card to stop him sending it.  Couldn't get in contact with him.  Then the dumb [***] called us a year later try to sell some stuff.  He wanted to sell us a barrel of the junk that didn't work.  We ask if we could sent the stuff back and get or money back.  He hung up the phone on us.  This guy is a fraud and crook.  Someone needs to shut him down.

Yep he's a crook. You may as well take a leak in your tank