Hey, @orangcrsh02 Welcome to Spotify Community and thanks for reaching out here!
About your payment issue, I recommend that you take a look at this support article to get help with it, initially. Perhaps you have two accounts liked to your credit card (or another payment method you use). So, I suggest that you take a look at your Receipts page and check if there is more than one receipt in the same month.
About your username, it's not possible to change it. You should have created a custom display name when you created your account. Now, you need to create a new account or link your Spotify account to your Facebook account. More information here: