Hi,
In order to create Technical support request in portal, you need to have a minimum of Standard level support. With Developer level support you need to post your question here on Q & A, and only if necessary an External Staff person will open a technical support ticket on your behalf.
What issue are you having (besides creating support request)? Are you trying to deploy MySQL Flexible server and it is failing? If yes it is likely due to capacity limitation and you need to create quota request. I can give you instructions on how to create quota request (they are free).
Please click Accept Answer and upvote if the above was helpful.
Thanks.
-TP