She's awfully cautious for someone who could make a slave merchants disappear without a fuzz.
Also I feel like she has some options. Like what even is his claim on her at this point? If its legal surly she looked into the laws regarding it. She would be what a debt slave because of him spending on her growing up? A debt slave should be able to buy their freedom or somthing. Was her slavery even finalized? Does she count as a escaped or runaway? She is worried about that, but I don't think we ever got confirmation. Like we don't even know if its a legal claim or not. Hell do we even know if slavery is legal in this series? For somthing so major that she has been laying low and avoiding attention the entire series it feels like somthing that should be at least a little fleshed out.
At the very least she absolutely could have the prince step in, hopefully she will shortly. He should be able to do that without to much attention. If she helps out in the fight or somthing he could simply say it was to repay her for helping, he could even just claim he likes her and force buying her off then freeing her. There are just so many ways she should be able to put this to rest. Hell how focused on her even is the merchant? Like she was reported dead, does he really have people searching all this time? You would think he would just forget about a orphan and more on to another.
Its just been a plot point for so long with no details or being built on at all.