http://www.macworld.com/article/2953139/ios/how-to-check-your-data-plan-usage-on-your-iphone.html
Let us know, if you want more tips on what you should and shouldn't backup, if you decide to do a reset.
For example, your app list you should take a snapshot of, and maybe email it to yourself or similar, but you don't want to just re-install the current apps, since this might re-enable the issue your'e trying to "filter out" by doing a reset.
*If this (or another post in this thread) fixes your problem/issue, please mark it as solved, and I'll tag it, to make it easier for others to find the answer(s). Thanks.