cash accounting for customers money?

I loaded some funds into the platform and they accepted it no problem. However once it was in, they prevented me from using it for some work I needed or withdrawing it back to the same bank account it came from. They put me through an onerous KYC process which remains ongoing.

If they were truly worried about KYC, I would have thought they should have put me through this KYC process before I was allowed to deposit funds and not once the funds were already in the platform.

The process has been overly difficult, so it got me thinking that this was something they were trying to do on purpose. I wonder how they use the cash captured in the platform that is restricted pending proper KYC from the users as I imagine that must be a large amount of money? I would expect many users would just give up eventually and loose that money.