I got a thousand users the first month on an app that went well. And about 200/month on something that doesn't go so well. This is also a small market, about 1/10 the size of the US.
I'll be frank here. It's like a date. If you don't think it's going well, it probably isn't. It might be doing okay, but it's probably better to move on.
If people aren't lining up to give you their money, it's likely not working. If it is working, your focus would be scaling, dealing with complaints, getting frustrated yet excited that there's too much to do.
That doesn't necessarily mean the product is wrong. It could mean you have the wrong market, wrong marketing channel, wrong pricing model (imagine if Facebook tried to charge membership or Netflix tried to monetize from microtransactions), wrong pitch.
One thing that always works for me is asking, who is the best competitor? And trying to build a product that is 10x better.
How do people do split proceeds now? They write out the math on a piece of paper, transfer to friends. Cash or click click bank account details. Is your product 10x better? Probably not. It's not too hard to do as it is, and it's more effort to sign up.
What about someone who does this a lot? Course seller, or freelance teachers for a studio. Well, they probably have done it in a contract, where they collect a sum and then pay it out. It's a burden, but is it a burden worth paying 6% + the cost of figuring out a new system?
Your fee system could be off too - I strongly dislike pushing fees to customers, because it feels like a dodgy 'hidden cost' thing. The reason people offer "free" shipping (i.e. write costs into the price) is because this puts off customers.
Alright, so who would actually have this issue so badly that they would be happy to pay 6% to get it off their hands?
A large scale company probably has integrated it into payroll, and at some point it's cheaper to just hire someone to split the bill. So you'll want something medium sized, maybe hectic and complex. Event management perhaps? Or training. If so, you'll actually want to be approaching those target clients directly and asking them. Asking your friends and family, or posting on HN will likely just give you fake data - your effective customer base could be 0, but is being floated up by supportive people.