It looks like your problem has been solved but just wanted to shed some light on my Stun Handler module. It can be used across multiple scripts and is fully customisable to suit your needs.
To use it, all you need to do is require the module. Whenever you want to stun a character, send the humanoid and stun duration to the function.
The function checks if the time remaining from the previous stun is shorter than the new stun, if it is shorter, the duration is updated to the new one that was sent.