I recently ordered a dozen things from Amazon from six vendors. All the things were pretty technical -- ethernet switches, fiber optic cables, transceivers, things like that. This is normal.
Four of the six vendors asked me to review their products. Two asked me multiple times over the same order.
Here's my policy, and I urge you to consider the same one:
I will only leave a review on a commerce site if I have an unusual experience to report. An unusual experience is either surprisingly good or exceptionally bad. I won't give any feedback for a transaction in which I paid the agreed amount of money, received the product in a reasonable time, and the product worked as expected.
Adding reviews outside of that policy has two negative effects: it adds useless noise to the review section, and it tends to inflate star-system grades.