Of course, if the sender can cancel transactions at their discretion, that enables another class of frauds. The solution has to lie in some trusted centralized party outside the payment system [0]. Chia can't solve this. A banking system and legal system can.

[0] Goharshady, A. K. (2021). Irrationality, Extortion, or Trusted Third-parties: Why it is Impossible to Buy and Sell Physical Goods Securely on the Blockchain (arXiv:2110.09857). http://arxiv.org/abs/2110.09857