What should I do if I can't get a message from my mobile phone when I pay the phone bill? Alipay also shows that the transaction is successful! ?

The success of the transaction means that you pay successfully, and he recharges you, but it does not mean that the recharge is successful. You can tell the seller to check it. If he says the recharge is successful, you can ask him to send you a successful picture. You can also call 10086 for further details. If it is confirmed that it is not charged, he can't charge it and apply for a refund.