if you both speak English as your first language, but this was not the case here.
Might be worth backing up the headset transactions with standard visual signs. Open the DV window on the headset man's side (should be commander's side anyway, but you can't guarantee it), and use the clenched fist/open palm signals throughout and constantly. For belt and braces, ensure on the turnround that the headset man/woman understands the standard signals.