Once you have submitted your ticket, you will get a reply from a support agent pretty quickly. You then need to engage with the agent and provide him with any information (sometimes screenshots) so that he can find out exactly what your problem is and get to fixing it.
You can reply to tickets from the self-support portal by doing the following. .
Quick guide to replying to tickets:
Open up the online version of the support URL from your email
Once you have read the conversation, click on the Reply button
Type out the message you want to send to the agent
Click on the Send button
Similarly, you can send out as many replies as it takes before the issue gets resolved.