My suggestion would be to try to reply to the comments (if possible),
If you have time to create elaborated posts, maybe you can also take a few minutes every day for commenting and replying?

I see nothing wrong to do with your earned money whatever you please. You created nice posts (you invested your time), and other people enjoyed your work and upvoted (paid for) it. I would not downvote anybody for using their own money ... but what I would do or not doesn't matter much here.

If they don't stop to downvote you, maybe the only way is to create a new account ...

Anyway: good luck in future! :)