If you lose the mobile number associated with your Shopee account, you can solve the problem by following the steps below. First, try to reset your password using your email address through Shopee's password recovery function. If this method does not work, you can try to contact Shopee's customer service team through Shopee's online customer service or email and provide your account information and other verification information so that they can help you change your mobile number. Finally, it is recommended that you regularly update and back up your account information in the future to prevent similar problems.