The confirmation email you received when you registered for the Certification Exam included the amount you paid for the exam and serves as a purchase receipt.

You may also generate a receipt by logging into HUDHousingCounselors.hud.gov, visiting the Exam Status Center via the Exam Pre-launch page and clicking "Receipts" in the blue header. The receipt will not stipulate payment type.

For a reschedule receipt, you would want to contact Kryterion via their Webform: Go to Contact Support, then complete the form, including a detailed description, and submit. Webform responses may take up to 72 hours.

Sincerely, 

HUDHousingCounselors.hud.gov