I buy credit 5USD but my credit balance still Minus credit and no balance
https://image.mudfish.net/i/smxoUb
https://image.mudfish.net/i/qa7tJ5
Are you using KIS (Kaspersky Internet Security) product on your desktop? If then please check Debugging issue for Mudfish v5 link to solve this issue.
At least I can see that your payment was handled properly.