Hi There,
Thanks for reaching out, I was unable to find a Developer account in our system under your details. If you have not signed up for a developer account you can register HERE. Once the registration has been complete you will then have the developer tab in My.MYOB where you can register for your API key and secret.
I did find a Trial account under your email which looks to expire in a couple of days however this should still let you log into My.MYOB while this is active. I recommend ensuring you are using Google chrome and clearing the browser cache as sometimes this can cause issues when login into My.MYOB.