Huge amounts of data usage on iphone 4S

For the last 3 months I have been battling with huge data usage. I'm lost as well as my provider (Rogers). For the month of April I used a whopping 6.84 GB. I have a print out for usage each day they range from 114418.00 KB to one day hitting 1385496.00 KB. The month of May repeated with total usage of 5.82 GB with daily usage starting at 95759.00 KB to the high of 760411.00 KB. So far im 12 days into my June billing, I'm now sitting at 3.3 GB my phone alone.

For my info, both myself and wife got our iphones the same day. We have only Facebook, Google, Weather, Banking and some game apps such as angry birds, candycrush, solitaire, etc. My wife and I use them about the same, with most usage on Facebook. The odd video clip on facebook is watched as well as uploading some pictures to it. My wifes print out shows April usage of 315.13 MB and Mays usage of 445.21 MB, she is at 78.3 MB so far for June. We have a shared plan with 2 GB per month usage. Before April's bill we were averaging between 800 MB to high of 1.3 GB combined.

Rogers is aware there is a huge problem and are crediting me some of the overage not all each month which is in excess of $100. We just do not know where the usage is coming from. My latest thing we have done was a system restore. But even since that was done last night and being on wifi. Which by the way our house has,and we use it when we can out of the house I have gained another 200 MB in 24 hrs.

What in the world is going on? I'm ready to pitch this thing all together.Our PC being hooked up to satellite Internet, we have a hard time getting to 6 GB and we use it for everything!

What should we be doing? And yes I close apps, load any apps or updates connected to our PC, and no one uses my phone but me. Our children are still in kindergarten so they are not using it.

Thanks