Depends, if you paid by
Family & Friends, can't do a refund
If it was Goods & Services or an Invoice, then you may have a chance to make a refund.
Either for fraudulent work, plagarism, extortion, manipulation, but honestly I never had to make those so I don't know the process or what things do work as a refund.
@abigaillmartin, UUUUUGHHH promoters are honestly the worst thing ever. They are so annoying, I also say the same as to the artists
Did I make a plea for your services?
Did I ask you specifically?
Did I complain about low engagement?
I basically scold and nag them as if they were little children, got one some time ago that not only bothered me via private but also self-promoted his services on my page.
I told them how disrespectful, out of line, unprofessional they were.
Got a "I'm so sorry, sir. I deleted the comment sir, I won't bother you anymore", motherfrusker even assumed my gender KJADHSHJADKSSDHJKA
But to be honest, promoters are so damn stupid like. They steal images of growth from other creators to make it look as if they """"""helped them""""""" grow.
The thing is, no one wants to hire services of ""promotion"" because it is not actual promotion, since they likely use bots, bots are a big no no on Tapas and Webtoon, on Webtoon there has been creators who got nuked for fraudulent use to buff their views just to get Ad Revenue.
Besides, bots do not provide engagement, just views or maybe likes based on how you set them up.

And since I'm at it

Left is stolen from Purrfect Crush, Webtoon France's Original series.

Middle is stolen from Third Shift Society, another Webtoon's Original series.
Not sure where the right one is from, but definetly also from Webtoon, judging by the lettering of the explosion effect.
Considering they do have more than 1K followers and a person I know do followes them, its probably one of those people that screwed up and a hacker took over. Happens quite often, but I see these problems more on Discord than on Instagram
LOL, called them out and noticed another one did as well.

I also confirmed in case if it was a stolen account, it isn't. Most followers they have are also bots.