Hey there @BungieGumm, Could I take a look at your in-game shop? Just take a screenshot of the store under the "NEW" category.
Are you from Steam? You must be Level 15 to use RedFox Credits with Steam Wallet. There is a level requirement in place to help combat fraud.
I am not from steam but now that has me wondering why they even allow a newish account to buy premium currency in the first place it is not a new account I just didn't pick the game back up till now.
Honestly not much I can say on the Billing side of things. Non-Steam users should be able to spend their RedFox Credits after reaching Level 11.
Was given out to accounts that registered and logged in around the time RedFox took over Rumble Fighter, and then was given out during some events.