This reminds me of when I went into the Verizon store. There was a guy there with a smashed iphone. They explained he had to purchase a replacement as he didnt have insurance. Looking resigned he agreed to this but then asked how he could copy his emails, contacts, music etc. to the new iphone. They told hi mthat all he had to do was resynch with itunes. He looked lost "what is itunes" he asked. The poor guy had this $400 phone and had no idea whatsoever how to use it. He had never synched it with itunes, he didnt have a computer even (which for an apple phone is kind of a must unless you have icloud). They poor verizon assistant looked sort of shocked and didnt really know what to say. She kept vainly mentioning that he needed to synch with itunes and wondered how in the hell he had managed to use his phone at all. Of course if he had had android none of this would be a problem really.
To the question at hand. Assuming you have actually got a google account and logged in then there really is nothing to be afraid of.
BTW Orange is one of the Uk phone networks. Like Verizon many of these companies just dont understand that Android at least doesnt require backing up of contacts, emails as its done automatically. Nothing is really stored on the phone in that regards. If you lose your phone you will never lose your contacts or email (well at least if you use gmail that is).
Of course if you dont have a google account and have never sycnhronised your phone with google then you are more or less on your own, like the poor iphone guy above.
When I bought my nexus the verizon guy spent some time fiddling with the phone before giving it to me. I was in a rush and eventually asked him what he was doing? He told me he was copying all the contacts from my old phone to the new one... DOH! I told him that was not necessary thankyou and maybe he should learn a bit more about android...He looked very suprised when I said that you never had to copy contacts around on android that it was done automatically.
If you use google music, google+, gmail and google voice then effectively nothing is stored on your phone.
Every movie I take, every photo I take, all my music, text messages, chat sessions, contacts and email are all in the cloud. If I lose my phone or my company wipes it.. I dont care.. jsut need to resynch with google.