As a rule of thumb, try to have all this sorted out before calling F5 and asking for help.

1. An updated qKview. Preferably taken while the issue was happening. Watch your CPU usage before taking the qKview though.
2. If it's related to an application, a tcpdump of the client's connection while the issue is happening. If you have a client-ssl and server-ssl profile, make sure to capture the TLS keys.
3. Make sure your hardware and software are under support.
4. The serial number of the box. You can get it with "show sys hardware" command. A list of useful commands can be found here.
5. If the serial number is not already registered to the user opening the ticket, you maybe asked questions regarding ownership, like contracts and so on.
6. Be mindfull of the severity levels defined by F5.
7. Here a list of F5 support phone numbers across the globe.