Didn't do much comparison before I sold it to someone on HF, and he's now selling it.

FS: Grado GS1000 Mint - Head-Fi: Covering Headphones, Earphones and Portable Audio

There were some subtle differences between them, but that was placebo probably since I didn't AB them side by side.

You can either send them back or, if you want to fix it yourself quick and easy, just get some metal epoxy, use it sparingly, and make sure to keep the epoxy in a ziplock bag, available, at at the ready, for the other earpiece (when it, too, falls off).