Hi Mahshid,
You may contact Pearson VUE directly to reschedule:
https://home.pearsonvue.com/microsoft/contact
If above does not solve the issue for some reason, please ask your question in the Microsoft Certification forum using link below. There are support moderators over there that will respond to your question in 1 business day and can assist with getting your certificate to show up:
https://trainingsupport.microsoft.com/en-us/newthread?threadtype=Questions&forum=mcp
Please click Accept Answer if above was helpful.
Thanks.
-TP