You get those emails at random (my first). Once that happens, the 6 hours countdown begins and you have to fulfil the requirements which come in 3 tiers. After which, the benefits are credited.
snip
If you happen to wager 0.05 BTC, you unlock the benefits from all tiers
Wow, those are some nice rewards. Can you or someone else let me know what subject does the email have ?
I would like to scan my emails to see if I have received any previously and can be prepared the next time I get it.