Apple purchase wont go through
So I bought some robux (in-game currency) for a game called roblox after I got a 25$ iTunes gift card, and it gave me an error saying there will be delay. But it never went though and took 5$ out of my iTunes account and didn't give me the robux. I don't know what do do. I logged in and out of my account, restarted my phone. I tried canceling it before it went though but I couldn't find out how. Any help would be appreciated. Thank you!
iPhone 6s Plus, iOS 13