Mcotter- We are here for you! Please keep in mind, if an application is running on your device, it may use data while "tabbed out" (background data). It's definitely unfortunate that so much data was used, but it would be correct. Were you connected to WiFi at all at the time this happened?
Please also ensure you mark this app for "Restrict background data" to ensure it does not happen again.
TylerK_VZW Follow us on TWITTER @VZWSupport If my response answered your question please click the Correct Answer button under my response. This ensures others can benefit from our conversation. Thanks in advance for your help with this!