Wechat WeChat business lottery, is it illegal to not want products or prizes?

It is illegal to refuse products and prizes in the WeChat merchant sweepstakes.

But I think when you buy a product, the manufacturer made a lottery promotion, and you won the prize, which is also you. The contract purpose of this product purchase includes the invitation to draw a lottery. The reason why I bought this product. One of them is that he won the lottery and has not fulfilled the contract as invited. I think this is his. He violated the contract law.