I was hacked on RuneScape. What do I do?

Well, I haven't been on RuneScape for probably 2 weeks at most. I logged on once before today just to check who was on. Didn't look in my bank or inventory or anything. Today, I logged on and I noticed I have noted items in my inventory. Also, I noticed I was in Grand Exchange. I don't usually go to Grand Exchange unless I need the bank or the tree to teleport. I checked my bank, and I automatically noticed 300-something/400-something items in my bank. My bank is almost always full. I look around and all of my money, most of my herbs, the only armour I actually wear, potions, 9,000 Monkfishes, thousands of runes and a bunch of seeds are missing. Is it possible for me to look at all of the ips that were ever logged into my account? A list or something? I know that there would be one odd one out if it's possible for me to check.