Minecoins price increased

Today I went to buy some coins to purchase some add-ons, and when I noticed, the price of minecoins had doubled. It became simply impossible to buy any kind of add-on after that, and it wasn't a subtle increase. I'd like to know if there was a bug, precisely because the price doubled. I'd really like to know if it's a marketplace bug, or if not, if this can't be done another way? Or at least lower the price this Black Friday? Now even the cheapest add-ons are going for 12 reais, which is enough to buy lunch here.