Li received a text message saying that he had won the grand prize in the participation column and had to pay a deposit to receive the prize.

This is a common means of fraud. According to relevant public information, swindlers use people's greed and curiosity to send them false winning information and ask them to pay a certain "deposit" or "handling fee" before they can receive the prize. These so-called prizes don't exist. Once the victim pays the "deposit", the liar will disappear and stop contacting the victim, thus defrauding the victim of money.