There are three ways to contact staff.
In all cases, please include complete and specific information, without referring back to support forum threads.
(1) Feedback button
On the top right hand corner of any admin side blog page you will see a blue "feedback" button. If you click it then a pane will open and you can type your message into it and send it to staff.
(2) Contact Support Form
On the front page of you blog on the far left hand side you will see a drop-down menu under My Account and one of the selections is "Contact Support" click it and send your message on the form provided.
Alternatively, You can send an email to support [at] wordpress [dot] com.