I've logged into another account, and checked the coupon does work. Does not seem to be targeted although I may be wrong..
"Yesterday we accidentally sent you an email, which you weren't supposed to receive. We're embarrassed and sorry for any annoyance or confusion we've caused. We understand how important your emails are to you and we'd like to offer you this $10 coupon towards your next task. Coupon code: EMAILSORRY (Add when accepting an offer. Expires 30/11/17)."
where do you enter the code?