You say down votes aren't bullying... The dictionary seems to differ.

I'd love to see where in the dictionary it says downvotes are bullying.

So can you please explain to me why my posts/content is being down voted?

Nope, I'm not personally downvoting your posts.

So if my content is being down voted because of a service I use, yes I would call that bullying.

If the service you use only exists to upvote content regardless of quality in exchange for money I'd say it's a little more complicated then just "bullying". They may see what they're doing as a positive service for the community, countering a bad actor (SBI) and not related to your post's specifically at all. I'm guessing, I don't know the people that are downvoting you.