60 GB Flash Drive says its full when its empty

I have a san disk 60 gb flash drive thats less than a month old. I dont have the receipt from walmart so I cant take it back… I have quite a bit of experience with computers but  I have no idea how to fix this thing! I have comppletely wipped it more than once. When I first got it it wouldnt hold 60 gb and i figured it just needed to be formated. i used it twice and then had to take several things off just to add one thing on so I’d have to take about 2-4 gb off for every 500 mb - 1 gb. I’ve formatted it, I’ve defraged it, and I’ve deleted everything off of it. Currently it’s empty (even when you look into the actual file theres nothing being used) but yet I cant upoad anything to it. I cant reformt it, so theres nothing i can do. Im trying to drfrag it again bc its my only option but since theres nothing on there idk what it’s gona do.  I also dont understand why when it’s plugged in my computer reads 2 drives. A Hitachi HTS543216L9SA00 and the San Disc Cruzer Glide USB Device. Can someone PLEASE help me???

  1.  You’ve posted to the wrong forum thread, but:  call SanDisk Customer Support–and you have a warranty.  http://www.sandisk.com/about-sandisk/contact-us/

  2.  The last time I checked its policy, Wam-Mart will take back a limited number of items per year even without a receipt.  Also, if you charged the purchase, you might want to also bring your credit card statement with you.