UX to handle different pricing & stock

I design an e-commerce android app & its corresponding seller platform web. right now we have rather high rejection rate because we built auto-reject features. the auto-reject feature will filter out transactions based on:

• stock --> so out of stock items at the time of purchase will not be forwarded to the seller platform
• price & wholesale setting --> so if the seller changes the price & wholesale setting of a specific product, the product info will be invalid and auto-rejected.

The problem is on the payment. Since this e-commerce is not paid using credit/debit card, but with a bank transfer or offline payment point instead, we give 24hr window of our customers to complete the payment. The 24hr window is non-negotiable. Within that 24hr window, sellers can update their price, wholesale tiered pricing, or stock, hence rendering the active cart invalid. After the customer finishes the bank transfer, he/she will receive push notif of rejected transaction. This is a poor UX because the customers can only find out after they paid.

How do you handle such product info difference? Auto-reject doesn't give a good UX so I aspire to change the logic.

Thank you.