It's called 'caller id spoofing'. The people calling you can make any phone number show up on your caller id. They're making a number show up that charges you money if you call it and press a certain key.
At the same time they've disguised the messages on their pay by phone system as surveys. Those messages normally tell you what you're buying and how much it costs.
Check your bill for unwanted charges if you called this number back.
I hate these people too. It seems they would have better things to do than to waste their time wasting other peoples time. I don't understand what their gain or their goal is. I will add this number to my list of the many other blocked numbers that I have on my blocked list thru Sprint.