How do i get all of my iphone restored once wapping handsets?! Itunes has lost everything!

I brought my iPhone into store for it to be mended - for which the antenna has gone so I received a completely knew handset.

I previously backed up my old one before going into the store however when recovering all of my data/ photos/ contacts etc... it hasn't saved any of it! How do I get it all back as I cant of lost everything?!