Sorry, if your unit has an external/removable battery, we probably did not realize this.
You might want to make sure the call center is aware of this, but unfortunately, our repair department is not set up to sell parts although if you don't mind sending back your battery only for RMA (make sure nothing gets near the exposed battery contacts of your notebook while you are waiting), that's another idea.
Otherwise, if you are located in the U.S., you can check if the ASUS Store or U.S. eStore site is able to sell this part.
http://us.estore.asus.com/ http://store.asus.com/us/
We don't have a lot of notebooks with removable batteries these days, so apologize if we missed this and something you may want to remind us about.
Thanks and good luck!