iPhone 3- Was set up with someone elses iTunes account, are they able to access my phone? My phone recently for no apparent reason came up with the iTunes symbol and a pic of a USB cord.  Apple seems thus far unable to access any of my data-like my contacts which is the most important.  

My ex initially set up my phone on his iTunes account, he hates me now, and I never even gave the fact that he set up my phone with his password and id until this happened.  

is it possible for someone else to remotely access my phone if they have the itunes id and pw that my phone has been operating off of?  

i right away signed up for my own itunes account, but i am just wondering if it is possible he wiped my phone or installed malware.  

thanks
Find My iPhone can be instructed to remotely wipe an iOS device, if that service was enabled on your phone.

It can also be used to track the location of a device, which you should also be concerned about.  However, once the device is erased, it can no longer be tracked.

Further reading: iCloud: Erase your device remotely