I did the same thing but I saw the little ridges on the inside of the battery ring and STOPPED and then pounded it back in. You should be able to put it all back together. It's not rocket science going on inside that battery. It's just a battery and a switch and a couple of wires. Even if you can't get it back together you should theoretically be able to make a mod out of it, since it will still work.
That said, the Stardust is fail. I have had them and tried them out exclusively now for over a month and I HATE THEM. They have better taste than like a standard cartomizer but the vapor production, stiff draw, constant cleaning maintenance, and inability to take them apart has angered me to no end. At least with cartomizers I only had a cleaning day once every other week. Now at a moment's notice I might have to pour the juice out, wash the thing out, dry burn it, and then blow dry it with the hair dryer before I can use it again. Then I have to wait a little while for it to wick the juice and it becomes vapable. Plus they kill my batteries twice as fast.
As soon as I get the money together I am going to get a 1000mah Ego-Twist Variable Voltage battery or two (with charger - the kgo is NOT compatible with it), and I am going with the new Vision Vivi Nova tank. The Vivi Nova tank is, truth be told, ugly as sin and a bit expensive when compared to the sleek look and cheap price of Stardusts. HOWEVER, it is completely rebuildable and it's easy to take apart. The only drawback is that if you want it to last forever you should invest in a metal tank insert for them, which will make it look even worse and heavier than it already is. You'll need an adapter to make it look halfway decent too, otherwise it will look terrible on the end of a KGO or EGO. Then there is the cost and difficulty in selecting wire and wick to rebuild it. So I estimate it will be a 35-40 dollar investment, maybe even north of that, for just one tank that will last forever. The Vivi Nova also comes with 3 atomizers so you can always have 2 ready to go or try different resistances or wick lengths for them with relative ease. So that, in my book makes them superior to the Stardust.
Here is a link to some video reviews/tutorials from an affiliate of mine, Estarra (I do his theme song
Vaping Estarra - YouTube
I hope this helps.
edit:
I have cracked 2 of them inexplicably near the upper metal ring and ruined them. I also ruined one trying to get it apart with the pliers method. The whole idea that got me into the Stardust was so that I could rebuild them for cheap and have a long lasting tank. Reality turned out to be much different. The 5 that I have left, I use 3 different flavors that are clear and the heat of the atomizer (burning so hot trying to earn me a decent (at best) vape) turns my juices dark over a very short period of time and then clogs up the wick and atomizer coil making them even less long lasting and requiring even MORE maintenance. The "burned" juice I end up pouring in an empty bottle and maybe I'll try and use in a Boge Cartomizer or something instead of throwing it away.
