How to access dead-space on iPhone 4S?

Right, my mum came to me saying that her contacts had gone. So by accident, I restored her phone to the first backup that she had done thinking that it would get her contacts back, I thought that if this was going to do some irreversible removing that iTunes would have warned me, but alas, it never did. Therefore I thought that I could just undo this change. However, this back-up did not have her contacts on and at that point she had no photos or basically anything on it. So basically I've f**ked up by not backing up before I did the back-up.

So anyway, is there a way I can get into the "dead space" of where data goes when it gets erased?
Or if she takes it to the apple shop, could they help with this at all?
Is there ANY way to undo a back-up and get anything that was on her phone back?
She's still got all of her music, so shouldn't her other things be somewhere too?
When something is deleted, where does it actually go and how can you get there to restore it?
It's mainly the photos/videos she's concerned about as there are many Absolutely irreplaceable photographs.
I have tired "Dr.fone" and other 'recovery' software but that doesn't even find the photos. Shouldn't my mum have backed up herself anyway?
I could be extremely grateful of ANY useful advice with this please.

Sorry for all the questions but as you can imagine, she's absolutely fuming and so am I to be honest, (I still think she should have sorted her iCloud out or asked me to do it for her, at least) Thanks for reading.

You can have your mom sign on to icloud at http://www.icloud.com/...icloud.com and you can see what is backed up there.