Muckrock might be helpful with techniques to compel disclosure at a reasonable cost. Do you plan to file suit against the Richland County sheriff’s department due to their violation of SC’s FIOA statute?
There’s no appeal process in SC, so they know they can just stonewall you and you’re highly unlikely to try to sue. The law is also just ambiguous enough that you risk losing even if you did sue, so it’s a lose-lose for the filer.
I've been an investigative reporter for years, and now 3 years in S.C. dealing a lot with FOIA. There's a lot of ways you can push, but one way they can stonewall you without a good way to pushback is this high cost.