H2testw is how you can tell. It looks like you got a 2GB card tweaked to read like 32GB.
I use H2testw to test every microSD when it arrives.
Read the readme.txt file in the h2testw folder, or look at this.
http://fightflashfraud.wordpress.com/download-h2testw-free-and-test-flash-memory/
If you tried CHKDSK, you should cut your losses and just get a new microSD.
And you might also get in touch with Play.com anyway and make threatening noises about lawsuits, counterfeiting, fraud, etc.if you feel like it.
