Ienyrid m4 pro s

Hi there I have an ienyrid m4 pro s scooter and it won’t rev up past 15 miles an hour no settings have been messed with at all and no wires would I need a new throttle also the scooter only goes with left brake leaver unplugged

I’ve got the ienyrid M4 pro s+ myself to change the gears press m button 5 times will activate third gear.

ienyrid m4 pro s+ scooter price is down?