Does it show up on your Pearson Vue dashboard (I'm assuming that is your exam provider)? You can use link below to reach it. Be patient, there is a delay while it redirects multiple times:
If you can't get to your Pearson Vue dashboard for some reason you may contact their customer service to reschedule:
https://home.pearsonvue.com/microsoft/contact
You should also post your question in the Certification forum. The support moderators over there can help with issues relating to exams, your certification profile, scheduling errors, discounts, etc.
https://trainingsupport.microsoft.com/en-us/newthread?threadtype=Questions&forum=mcp
Please click Accept Answer if the above was helpful.
Thanks.
-TP