Iphone 4s hacked

I hope someone can help me here. I believe my phone is being hacked, in fact i have the evidence that someone is hacking my iphone 4s, the person is somehow able to read, access and screenshot text messages that I am sending and recieving, able to see my contacts and delete them from my phone and they have been harrassing me for months sending me messages about what they are able to do using free text messaging service websites that are too to count here in the UK. I therefore do not know who is doing it and how. They have sent me messages claiming they can access my account through icloud and i have removed icloud from my phone but they are still able to access my phone. I feel very unsafe. I went to the apple store to speak with the apple geniuses who advised me as everyone else that iphones cannot be hacked but i know for certain that mine is being hacked. Sometimes my phone just starts restoring itself without me doing anything. I have also been advsed to restore the phone as a new phone and not using the back up, which I have done but its still not helping. I was hoping to buy the iphone5 but i am now too scared to even buy it or any smart phone for that matter. Needless to say I have reported the harrasment to the police but they have not helped either, simply advising that there is no way of finding out who it is and if there is a "real" threat to my life in person then they can do something. Someone, anyone with any knowledge on what I can do please HELP