Yes,this is a hungarian promotion.
Promotion is: Every Monday we are waiting for extra prize at Unibet Casino! The offer may vary from week to week, so you should check your account every Monday.Our weekly offer is as follows: Play at least 1500 HUF on any of our Slot Machines and if you win, your winnings will be doubled up to 5,000 HUF.If you can not win, do not get bored, as 20 free spins will be credited to your account for compensation. (until wednesday 8 pm)
I won on Monday but did not double my winnings.