OP, what kind of revenge are you considering? If you are in control of something that this person wants or needs, I say yeah, go ahead and deny it to that person. I wouldn't advise revenge that could leave your hands dirty either in the legal or social context.
A couple of people I have dealt with and had to move on from have tried to reconnect with me and I just can't be bothered. Some may call that revenge. But still, if you've moved on, you've moved on. Just because someone is in your face trying to rekindle something does not mean that I have an obligation to be a yes person to this person.
Personally, I am not against revenge in principle. But I would advise that you ensure that you don't get your hands dirty, either socially, legally, financially, or any other way.
Princess Di was known for being vengeful. And she was up to a certain point good at it. Just when Charles was airing a documentary about himself on TV, she stole the headlines the next day by going to an opening. Her personal activities were always timed to knock the other royals off the front pages of the London newspapers.
the year that the Queen and her consort were having local parties with others who were celebrating their 50th wedding anniversary, Di went sailing with Fayed and his son Dodi and knocked that whole PR effort of the Queen off the front pages of the newspapers.
But as we know, her vengeful behavior caught up with her.......don't let it happen to you.