uff you really scared me ...
fortunately this is exact code that reduce amount of credit
// map successfully downloaded, reduce Vector maps limit
final int itemSize = (int) Math.ceil(sizeZip / 1024.0 / 1024.0);
so there is nice value sizeZip which is size of compressed file Locus downloaded. If you send me your email used in Locus store, I check what exactly you downloaded and how much credit was substract. I'm sure that because this system run more then year, someone should already noticed this if there will be such huge problem!!
Also reaction like "Pfffffffff.... $$$$$" is really not necessary. I'm not that kind of guy
And finally, I don't understand why you purchase a credit. You translated quite a lot of text and I already few times wrote to all translators, that I can send credit on vector maps for them!
And thanks for report above, I'll check it and fix these problems