We dont buy Platinum directly on PSN, Read below for how to get your Platinum on PS4-5
Be sure Crossplatform is enabled for PC Login for this process.
Link: warframe.com/cross-save
After you did Cross-platform is Enabled - ON (PC and PSN), We will give you the steps
Once you receive the platinum on PC, you can use the Platinum on your PS4-5 acc.
If you dont have PC to claim the Platinum
Enable Crossplatform, and send us your Warframe PC Login, I will do it for you!