Nice and all but based on RNDM1's comment, it might be safe to say that the author did not do much research into premodern society/economics or have a background in either field, and so with their lack of knowledge came this arc as a way to justify why Anna is so obsessed with money.
Could be worse.
It also just doesnt really make sense from what we've seen of the econonic and security bits of the capital.
There's guards everywhere and most of the nobility in the area would prob have some link back to the Monarchs so it'd be easy to strong-arm the guards into arresting anyone that even TRIES to force them into selling the loan agreements (if they really cared about it) and wealthy merchants would usually have some bodyguards or even a private militia (because they're wealthy merchants if they didnt they'd have been robbed of all their money by now lol)
So either their lenders are lying about being forced, or all of the lenders are complete idiots that shouldn't have any money at all (should've been robbed of it all by now if they didnt have strong enough bodyguards)
Plus Laura, Anna and Charlotte are directly connected to the queen, they could report the crime of these thugs to her and get them arrested easily as well.