As a rule of thumb: If marketing service promises more followers, it's most likely garbage marketing program. Also, if a company buys followers, it's either a garbage company, or they hired cheapest marketing possible. In both cases, avoid a company that buys followers like a plague, because that's not going to be an only thing they will mislead you.
That also either signals that team doesn't have smart people in it, or that they believe that their target audience is stupid enough that they wouldn't see or care. And what exactly you need stupid customers for? Money and scamming are the only 2 options they are perfect for.
You are driving a point, there's nothing that can be compared to organic marketing and the only measure that will make it possible is the ones we should opt for. I've read enough online and even seen for myself how they will promise you some internet followers, but in the end, it is just bots they are selling to you.
It got worse to the point that they will not give you the fake followers alone but also make them perform fake likes and impressions, but to what end? It's in selling the real product the person will know and nothing hurts more than having 5 million followers and still being unable to sell 5 products/services.