If I return a product or cancel an order, will the reward points I earned from those products be deducted from my reward point balance?

Yes. When you return a product or cancel an order, the amount of reward points you have earned will be deducted from the total reward points on your account. (Reward points earned on an order are deducted when the order is refunded, and the return is settled.)

If you earn points with a product purchase, spend those points to purchase product, and then return the original product that earned the points in the first place, a corresponding number of points will be deleted from your account.