Using the preferred support option depending on the issue you are facing is the best way to start have Microsoft support. You can go to your portal and create a support ticket. Go to http://portal.office.com and in the Support section, click on the New service request option:
You can read more at https://support.office.com/en-us/article/contact-support-for-business-products-admin-help-32a17ca7-6fa0-4870-8a8d-e25ba4ccfd4b.
Let's write something like Skype for business contacts as shown in the following screenshot:
Click on the ...
