This has happened to me a couple of times, I have purchased crowns in the Play Station store and then I get a message saying that the service is not available/is undergoing maintenance etc etc
Then the crowns do not appear in game and I have no idea if the purchase has gone through.
The first time this happened I checked my emails and saw that funds had been added to my wallet. However on the second occasion I did not have my phone and thought the store had crashed whilst I was making a purchase, when I went back in the service had been taken offline for maintenance so I thought it had not gone through. So I purchased crowns again.
Then low and behold the crowns appeared in game and yes I had purchased them twice!
I feel that this bug could be misleading other players into making additional payments that they did not intend to make.
I guess PSN are in no hurry to fix it though...