Do you have proof of your band purchase in your transactions ? If so, I think you can file a claim with Roblox for a refund. You can also try disconnecting and reconnecting in different browsers.
I’m sorry you ran into this problem, it looks like there was an issue during group creation and unfortunately left that group in an unusable state. We do see the purchase was cancelled, did you receive your refund for the creation? If not let us know.
As far as the group goes, you will need to create a new one to ensure it is properly created. Can you try again and let me know if it works?