Can I get a refund for a one-time hotel accommodation discount?

You can't. According to Ctrip's inquiry in official website, the hotel accommodation discount is not refundable if paid in one lump sum. But if you can't check in, you can call the hotel in advance to explain the situation. Basically, good hotel management allows refunds. After the hotel allows, you can call customer service and say that the hotel agrees to refund. If the hotel doesn't agree, you can call the customer service and let the customer service coordinate.