In the digital age, collecting and analyzing product data via cloud computing is crucial for product improvement. However, current solutions do not guarantee the protection of each client’s data from misuse, and there is no assurance that the information collected by third parties is from a reliable source. In this paper, we propose a new scheme for privacy-preserving and accountable data collection and analysis (called PPA-DCA for short), which uses decentralized multi-client functional encryption. This scheme addresses malicious data misuse by clients and provides a reliable method for third-party companies to collect and analyze data. With a verify-first-encrypt approach, we ensure that only verified clients can encrypt and transmit data, make our scheme more efficient than other works. Additionally, the scheme introduces a monitoring mechanism as a system monitor, capable of detecting any abnormal or malicious behavior of clients in real-time. Upon discovering unauthorized or malicious activities, the system can promptly identify and take corresponding punitive measures. Based on the standard assumptions on bilinear groups, the scheme satisfies static indistinguishable security, simultaneously ensuring the unforgeability, accountability, and privacy of signatures.