The complainant is blocked from using the card or encounters a chargeback, poor customer service attitude, errors in transaction refunds, the bank's unilateral adjustment of the limit, causing the complainant to be blocked from using the card or encountering overdue payments, and bank reconciliation is not timely. There are obstacles in canceling the card; the main problems in credit card marketing and promotion include: applying for cards under false names, failure to honor promotions, unauthorized modification of points, rules of preferential activities, etc.