I post this here since the support tickets only told me that they were redirected to the correct member of the support team.

When 4.10 came, I bought my first 2 chests of the Divine uprising event with the intention of getting Polar Vortex Kukulkan. After the first roll, I didn't get a coupon for a 50% off of the next Slavic chest roll. I thought it meant that it was an automatic thing:you roll the chest and it costs 150 gems. However, that was not the case and I ended up using 600 gems instead of 450.

Some time after that I log into the game only to find that I was given a coupon for a discounted SECOND roll of the Slavic chest.

I never used the coupon, as I had already obtained the item I wanted, but it costed me more than it should have.

Could I get a 150 gems refund?