I have purchased 1300 Star Gems yesterday, through Steam, and have not received the in-game yet.

I have purchased 1300 Star Gems yesterday, through Steam, and have not received them in-game yet.

Was this your first PSO2 purchase through Steam? If so, then there is a ~24 hour delay. If the SG doesn't show up in-game within 48 hours, then you can request a refund from Steam, or you can try submitting a support ticket through support.pso2.com .