Unlimited talk and text but still high bill (Verizon Wireless)?

So I have an iPhone 4 by Verizon with unlimited talk and text. When I first bought this phone I was paying 103.00 for a while, then it went up to 104, 111 and kept getting higher. So a few days ago i receive my bill in the mail and it said 160! What the heck.
I'm not buying any apps, I get them all for free, my data is extremely low… What is going on? Is there any way I can make my bill go down to it's original price? I'd much appreciate the help

Call Verizon and ask them why your bill is so high, maybe they made a mistake.