Hello @Manuela Bedoya ,
Welcome to the Microsoft Q&A platform.
Microsoft Certification Program is supported on their own forums. I'd try asking for help with exam scheduling in dedicated forums here. (Participate\Ask A Question)
Exams/Exam Registration/General Registration Questions
Exams /Exam Registration and Scheduling/Scheduling with Pearson Vue
Pearson VUE Customer service
Pearson VUE contact / chat
Hope this helps. Do let us know if you any further queries.
------------
Please don’t forget to Accept Answer
and Up-Vote
wherever the information provided helps you, this can be beneficial to other community members.