Thanks to the fact that I used all the promo codes for free spins provided by TonStation exclusively for the Bitcointalk community, I managed to reach the Silver League level just a day after I was promoted to the Iron League level. Which I recommend to all players, especially since it's easy to use the promo code - you can just click on the caption under the post to get into the app (if you logged in from your smartphone). The rest of the promo codes can be found in the posts of this thread above.