As someone who frequents Instagram as a way to grow my business, I often encounter Instagram accounts that comment on my posts with generic comments that could apply to almost any post anyone could ever make, they follow the comment with liking my post and following me. This happens 3-10 times per post I make, depending on the hashtags I've used on the post. If I follow them back, they will magically disappear from my followers list an undetermined amount of time afterward. After they make the initial comment and follow, I never see them engage with me again.
For context, there are a few different types of followers that you do not want:
Fake followers are, in general, followers that you get from paying a company that promises to get you 1,000+ followers. They are essentially inactive accounts that are controlled by the company's software to follow people.
Inactive followers are people that may genuinely be interested in what you're doing, but have stopped using the platform for whatever reason.
Ghost followers are people that follow you either for superficial reasons, or are using a bot to follow you on their behalf. Again, for superficial reasons and to bait you into following them.
Reporting someone for spamming blocks the account, and forces it to unfollow you. It may seem counter-intuitive to reduce the number of followers you have, but social platforms' algorithms seem to disfavor business accounts with unengaged followings. When these accounts follow you, they are ghost followers. They hurt your rankings, and they waste your money when it comes time to run ads targeted at your followers.
When you're ghost following people, the majority of the people following you will be ghost following you in turn. Sure, you may end up getting the numbers that qualify you to influencer contracts, but those contracts will swiftly be torn up when your low genuine engagement and lack of sufficient conversions result in wasting your clients' money.
If this seems like me whining about these spammers wasting my time (it is), it's more of an effort on my end to communicate that this isn't how the game is played. You're trying to cheat the game, and cheaters inevitably get banned. My recommendation is if you want to pay for followers, pay for an ad that will entice and engage your potential customers. These followers will have astronomically higher conversion rates and will spread and enhance your brand through word-of-mouth, shares, and consistent engagements.