There seems to be a difference between the available Store Credit of yours with the site currency you had picked previously. Would you like to:
Roblox TOP UP USD $8.47
Roblox TOP UP USD $8.46
Roblox TOP UP USD $17.97
Roblox TOP UP USD $46.75
Roblox TOP UP USD $457.92
Roblox TOP UP USD $195.57
Roblox TOP UP USD $185.55
Roblox TOP UP USD $53