Payments via Bitcoin are processed on the Blockchain network, which may charge a networking fee. This may also apply to Wallet providers charging their own fee. You will need to include these fees in the price of the challenge.
If we have received less, you will be informed via email to settle the remaining amount. Remember to check your Spam/Junk folders for this email if you have not received your Evaluation stage credentials.
Once the full amount has been settled, you will receive the credentials.