Um, i think ive been hacked?

Hi people, ok i need some advice, first of all i switch around a lot, from my home network, to my dads work network, which are about 45 minutes away, and when i try to log in it says that it has detected a change pattern and before i know it my account says it has been banned permanently...!!!!! i mean wtf!? i was just on last night i did not do anything? how do i get my account back? they sent me a email telling that someone reported that it might be compromised... but who? and will i still have my items, toons, gold, everything?? please help!