After each purchase of the template, I put reviews. In the case of one template, the second time my opinions are deleted. This is a simple opinion. There is no negative content. I noticed that other people’s opinions are also removed.
Sometimes and Author can request to have a review removed from their item if they feel it’s unjust, for example, if someone leaves a 1 star review saying that the item doesn’t work, but there are many other buyers who have had no problems, and the reviewer doesn’t attempt to contact the Author, then there’s no basis for that negative review and Envato has the ability to remove it.
To be clear, not every negative review will be removed. If the review has a good explanation and not just “Item bad”, then it’s going to stay.
Now in your case, since you said it wasn’t a negative review, then I’m not sure why it’d be disappearing, unless there’s many reviews on that item and your’s got lost within them?