I got down voted some times without reason, and I also know the user who did this but the support told me that there is no evidence about this.
However this is not the point of my question. I have some valid and correct answers that are downvoted:
I fell like these answers are useful and correct. I removed the first one because it seems like the first down vote triggered a vicious circle, so that some users (or goats?) was down voting it without reason, probably because they saw the negative score and trusted who gave the first down vote. Also the second (not deleted) answer is useful and correct.
Should I remove the second or undelete the first or what?