Is the unit new? Just that the specs quite clearly show the two wired output plugs as being conventional GA ones. (There are 2.5 and 3.5 mm input jacks on the control box for phone and music inputs). If someone has re-terminated the mic in a non-standard connector, I would take the previous poster's advice and change it back. But you can get adapters, e.g.
5.25 mm Jack (Male) to 1 x 3.5mm (Female) Socket Adapter - E-Sunrise
(I assume the mic connector on the headset lead is male, and you have to hope that any non-standard plug follows the usual GA mic wiring convention).