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
As to recovering the microsoft account also try resetting via the account recovery form
https://support.microsoft.com/en-us/account-billing/help-with-the-microsoft-account-recovery-form-b19c02d1-a782-dee6-93c3-dc8113b20c42
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