Mobile Payment

So, I bought 140 RP for 3.51 BAM with help of mine phone, I received RP. And then, when I tried to buy 840 RP, for 21.06 BAM, I did not receive RP, but I got charged with 3.51 BAM. And the thing is, mine transaction go bugged or something?! What happened? I got charged for same price two times, first time getting RP, and second time getting charged, but not receiving RP that I wanted to get for 21.06 BAM. Luckly, I was not charged with 21.06 BAM, but again, I got charged for nothing. Can someone explain to me why this happened?