Illegal. Although the consumer was told that this is a modified second-hand mobile phone during the sales process, this behavior has violated the crime of selling counterfeit registered trademark goods in the criminal law, so it is illegal. Mobile phones, called mobile phones or wireless phones, are usually called mobile phones. At first, it was just a communication tool. In the early days, it was also commonly known as mobile phone, which was a portable telephone terminal that could be widely used.