Help me for MongoDB exam coupon

I applied for the exam with the coupon but it shows invalid please help me , i mailed about this to certification@mongodb.com

Hello @CHANDRAMUHILAN_M_AI-DS! We apologize for the inconvenience. I replied to the email that you sent. Please let me know if you did not recieve it. Thanks so much!
-Heather

I received the mail of acceptance of my request.but problem is not solved yet!

@CHANDRAMUHILAN_M_AI-DS We believe that this problem is now resolved. Can you please attempt to purchase your exam with the voucher code once more? Please let me know if the problem still persists. Thank you!