I've only done it a handful of times, little ones, but the first time was huge. I bought a blue voucher I think. I didn't know that clicking the + sign would make me "buy" the voucher. I complained a few times but never got anything back even though I may have one time. One day, after complaining, I opened 4 boxes in a row with lots of diamonds in them. So, not sure if it was a coincidence or it was them paying me back
GC: ea_sweetface. Level 73.