1. System docking. Occasionally, there are omissions in the docking between the banking system and the mobile phone card operator's system, resulting in the failure to transmit information;

Second, the credit card banks didn't give you SMS reminders for small consumption. Now at least one-third of the banks don't provide free SMS notifications for consumption below 5 yuan, which must be paid by consumers, and it is free for consumption above 5 yuan (inclusive);

third, the mobile phone used does not match the mobile phone number reserved when applying for a credit card at that time.