Logo Rip Off! What to do?!

There is nothing creative about creatives. Plagiarism is what they do best.

+1 squillion. they feed off the creativity of others and call it their own.

If you had trademarked your design, on the other hand, or could prove prior art, then you should enforce it pronto.
The important thing, law-wise, is to find a way that you can verify the very first date that your image was created and made public. Then it's up to a lawyer to write to these other Milk people and tell them to GTFO or get sued. make sure you don't approach the other Milk people without legal advice, as i can imagine that there are various legal terms/protocols that must be used. I've heard of people getting screwed because they didn't do something 'just so' and their otherwise very strong case being thrown out of court.