Hi,
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 merging your accounts:
https://trainingsupport.microsoft.com/en-us/newthread?threadtype=Questions&forum=mcp
Please click Accept Answer if above was helpful.
Thanks.
-TP
After posting your question over there, make sure you check it periodically for a reply from a moderator. Reason is, their system may not send you email notifications and if you don't respond to their reply within a certain period of time they will lock your question.