Fix VPS Firewall, Restore cPanel

Access to both WHM and cPanel on my Linux-based VPS has stopped completely. My hosting company says the problem sits in the network layer, and from what I can see the firewall rules are the most likely culprit. I need someone who can jump in over SSH, audit the existing iptables/CSF configuration, reopen the required cPanel & WHM ports, and adjust any related network settings so the control panels become reachable again.

Deliverables
• Full diagnosis of current firewall and network configuration
• Safe reconfiguration that restores access to cPanel (2083) and WHM (2087) without exposing the server
• Brief report of the changes made and commands used so I can keep them for future reference

Please be comfortable working on a live Linux VPS environment and finishing the job in a timely manner.