Hey mate. I've also found that resteem services are rarely useful. Some people like them however I've never gained anything substantial from them.

I have sold my votes through minnowbooster in the past but generally limit this type of behaviour as well. I personally prefer to give my upvotes to deserving content.

Also, if you do want to purchase upvotes then you'll need to use this tool:

https://steembottracker.com/

Using this site will let you know when the bots listed will be voting next, whether the vote you buy is likely to be profitable or not, and what restrictions there are when using the voting bot (such as the age of the post they will upvote).

@coolbot probably isn't listed on this site. Mainly because their upvote is only worth a few cents.

If you ever need anything you can find me on the PAL discord server. My username there is the same as here.