I received a phone from eBay and Facebook , twitter and eBay are not working :/ ?

[Jack]

Hi there, I bought a samsung phone from eBay and received on Saturday just passed. It was from someone who claims to be a private seller but acts like they are a business.
Firstly , the listing didn't say that it didn't come with the USB cable or the manuals but these aren't in the box.
Also , the Facebook , twitter and eBay apps (not tried any others yet cos I've just got the AppStore working cos there was no USB cable cos it's windows phone 7 so you need to connect to a computer first) aren't working when I have a perfectly good 3G signal.
So really what I'm asking is what rights do I have and how should I go about getting my money back?

Thanks for any help
Hi it did say no returns but only in the postage bit.
And no there was no list of what came with it :/
Also I tried the Bluetooth last night and after trying quite a few times it wouldn't work :/ I think it must be faulty but will they have to take it back?