automatic reward based on points - help


I request your help because I 'm not sure how to manage a reward system.

I would like to provide a 10€ discount coupon, when client’s reward points pass 500 points.

Rule #1

Conditions : reward points greater or equals 500

Bonus : Give coupon : Rule #2

Rule #2

condition : Automatically generated coupon : No data found

Bonus : Order discount 10€.

My problems :

Every single client gets the promotion (!!)

I don’t know how to reset reward points to 0 when this is generated / used (is it automatic, i stopped the system before loosing money

thanks for your help !