Depends on who he's comparing his server to.
Generally you would want to put the price you are paying in the title so the YouTuber would want to read your email.
I assume that he/she gets a lot of fan mail to the business email as well so he/she probably might have deleted it by accident.
Another option would be to go through their manager.
The manager does take a percentage cut, but you would probably receive a quicker response.