I would NEVER give the chocolate back to her because then she essentially is rewarded for buying it for the OP to begin with.
You would think so, wouldn't you? I'm so pleased I posted here, you all share my logic. But MIL doesn't see things the same way as ehell. She's actually pleased if DH or someone else gets it. MIL sees that as her being generous and giving someone an extra present.
My best friend explains it like this - MIL and I are are from different planets. BF and I are from the same planet. Our planet is much nicer!
The dark chocolate was an exception. It's usually something DH really likes and he doesn't like dark chocolate.
Ooh - you may be right! She gave him these at Christmas http://www.ferrero.de/#/rond
apparently they were divine! So she may have thought she'd get them back and it backfired. I really like that idea