Pbag2

After a battle I had a message pop up for the 1000rp Reward Point Voucher and clicked ok to accept. The message read the same as what you'd see under Gift Shop > Voucher. I didn't buy this and wasn't on any menu when this popped up so I guess it's a random reward based on time played perhaps. I can't find this however... Can anyone help me with where I'd be able to access this?