Hi Trishla,
If you go to "See your profile" and look in the top right corner, you'll find the merge option. Also, as you mentioned, include the certification you obtained in your last organization. Follow the link below to create a request: https://support.mendix.com/hc/en-us
Mendix's support team will assist you with this, as they helped me with a similar issue. I hope this helps you out!