TracFone Possible Phone Scam Nationwide

I may be wrong, but I have noticed a disturbing trend with TracFone. I bought one of these cell phones for my daughter and keep her supplied with minutes so that she can call her friends or phone home. She tells me though that her minutes are taken up by the loads of spam calls she gets. 

What happens is I buy her minutes and she gets more spam calls. They come as voice mails. But the number only appears on her screen for a few seconds so she can't tell who called. The number does not show up on her menu for received calls, so she is forced to call back to to her voicemail to listen for who called her in case it's someone she needs to talk to. This eats up her minutes. 

This got me thinking, I wonder if this is some sort of scam to get people to buy more minutes. The minutes they have to waste calling their voice mail to listen to all these scamming messages, and the minutes thqt they only intended to buy in the first place for real calls. 

Might I suggest to TracFone that if they are not pulling a fast one to get peple to buy more minutes that they set up some sort of spam detectors like internet ISPs use. I'm not suggesting that they listen to people's phone calls, no one wants that, but that they keep a log of phone numbers that the scammers use and block those. Further, if they could report those to the authorities that would be helpful. One call she got actually told her she was being sued and had to call them back right away. A bald faced lie. She's only thirteen, is a straight A student and no trouble to anyone.