I am having the same issue. My husband and I rarely go over our 4GB. I received a text that I was over and charged $30. Days later I received a text saying I had 10% left and then very next day I had no data. I work from home and I am always on my home WIFI. My husband has WIFI at work he is connected to also. Something is not adding up. I have been with Verizon since...Well a very very long time!
I am shopping for a new provider.