Most shops do not lose the sale because the product is wrong. They lose it because the reply arrives after dinner, after another seller, after the buyer closed the app.
The fix is operational, not motivational: know the size is there before you type, and send a payment path in the same thread. Screenshots of a card number are not a path. They are a second job for whoever checks receipts at midnight.
Start with the repeat questions. If a post gets the same “price?” comment forty times, that is a mapping job, not a typing job. Automate that one post, keep the rest manual, and measure how many chats become paid orders before you expand.
Put this into practice
Create shop account