1. Collect evidence: keep all relevant documents, contracts, memos or correspondence records with bank staff. These are all the evidences that you reported.
2. Identify complaint channels: You can report this behavior through the following channels:
-complain to the bank's superior management organization or internal complaint channels;
-Report the bank's illegal acts to the local banking supervision department (usually a branch of the People's Bank of China);
-Complain to consumer associations or regulatory bodies.
3. Contact the bank: Before you complain to the relevant institutions, you can try to contact the bank to discuss the problems with them and seek solutions. In this process, we must keep relevant communication records.
4. Submit a complaint application: according to your specific situation, choose the appropriate complaint channel, prepare relevant materials, and submit a complaint application to relevant institutions.
Please note that these steps may vary from country to country. It is best to consult local lawyers or relevant institutions to obtain accurate legal and complaint procedure information.