In shift i have redeemed 20 golden keys once, 25 golden keys twice, 10 golden keys one time, 3 golden keys five times and 5 golden keys 41 times and the game was showing that i only had 116 instead of the actual number that i should have which is around 300 (or 255 since the number doesn’t get above it until you spend some keys). I also spent some keys, right now i got 98 so i don’t think it’s that reserve and active balance thing.
I’m having the same problem. I contacted support but they won’t reply to me. I have 75 keys but I redeemed 15 golden keys and should have 90.
The codes weren’t expired either because my sister used the same codes on the same day and it counted for her.
Hey, that might help you http://orcz.com/Borderlands_2:_Golden_Key#Bookmark_Here
You won’t get your 15 keys but at least in there you can get like 300 keys.