Steps for 12315 WeChat to complain about merchants without registration codes:

1. Open and log in to WeChat APP on your mobile phone.

2. On the main WeChat interface, click on the menu below to find the mini program.

3. In the mini program interface, click the search icon in the upper right corner.

4. Enter 12135 in the search bar and click to enter the mini program.

5. On the national 12135 platform interface, click I want to complain or I want to report.

6. Complaint instructions, click below to agree after reading.

7. Select the unit to complain to, enter the company name or credit code to search, explain the issue to be complained, and click Submit.