I had a similar situation with her. The six-month point for acommission was approaching so I filed for a refund with PayPal. She finally responded to that and was very angry about it. Things broke down to the point that I no longer wanted to speak to her.
I let her keep the money (I didn't think it was worth potentially making someone homeless over, as she claims). So despite getting money from me for doing nothing and even recycling the YCH I'd claimed, she posted a 'blacklist' on her TOS calling me out by name that I had to get taken down by the FA admins.
I seriously doubt that a TOS where the artist tries to forbid chargebacks under any circumstance is valid, especially when journals on FA can be edited at will. PayPal certainly doesn't agree with the idea.
She seems to have no idea how running a business works and has a strong sense of entitlement.