So titan poker is running a casino promotion in which you get 30% of your casino losses refunded up to $1000. Now in the fine print in the terms and conditions it says you have to wager 20x your bonus to cash out. Is this profitable to play blackjack? If so, whats the most profitable way to play? (max bet is $500)

If it's as you say it is, it is profitable.

You should max bet until you lose $1,000 or reach a target you're comfortable with (utility function).

If you do lose, you should roll over the refund slowly, small bets to insure you get as much back as possible, should be in the neighborhood of $270 returned.

It seems to me like the best way to play would be to stop if you are up more than the max bet but keep playing until you are down $3333. Then once you get your $1000 casino bonus then obviously wager 20x that amount whether you are up or down until the entire bonus is released. I think small bets would decrease your variance but be more time consuming.

How would you calculate he chance of you winning $500 vrs you losing $3333?

Yeah, I made a mistake, I thought he meant refunded on $1,000 worth of losses, not losses refunded up to a total of $1,000. In that case, yes you should definitely be willing to risk more.

But winning $500 should not be the goal, it should be much higher, $1500 at least.

but once you start winning you have no compensation for losing and it just becomes normal blackjack again and therefor -EV.

The casino has the edge you just are wagering 30% less then you think (or w/e) when you lose but you will not win any additional monies