According to the General Administration of Quality Supervision, Inspection and Quarantine, someone once asked the same question as you on the Internet and responded as follows:
Question: Where can I check the authenticity of the special equipment installation, modification and maintenance permit?
Answer: The special equipment installation, renovation and maintenance licenses are divided into certificates issued by the State Bureau for examining and approving enterprises and provincial certificates for examining and approving enterprises. For the certificate of the enterprise approved by the State Bureau, please visit the special equipment safety management website of the AQSIQ website. For the certificate of the enterprise approved by the Provincial Bureau, please consult the local Bureau of Quality and Technical Supervision.
If you want to ask more details, you can log in to the "General Administration of Quality Supervision, Inspection and Quarantine" and enter what you want to ask in "I want to leave a message", and the staff of the General Administration will reply you. In addition, you can also search by keywords.