Legal analysis: consumers can complain to the consumer association where the consumer is located, or to the consumer association where the responsible person is located.

This organization has violated your initial oral agreement, and there are several ways to solve it:

1. Negotiate a refund with this institution, and both parties will make concessions to reduce the time and money costs brought by litigation.

2. If no agreement can be reached, you can bring a lawsuit to the court to explain the losses caused by the agency's breach of contract, request the court to judge the agency to return your deposit, and you can ask it to compensate for part of the liquidated damages.

3. It is unreasonable for an institution to refund money but deduct it. Even if you don't have a certificate, the organization must have proof of your payment, and you can't deduct money just because you lost your certificate.

Legal basis: Law of People's Republic of China (PRC) on the Protection of Consumer Rights and Interests.

Article 5 The state protects the legitimate rights and interests of consumers from infringement. The state takes measures to ensure that consumers exercise their rights according to law and safeguard their legitimate rights and interests. The state advocates civilized, healthy, resource-saving and environment-friendly consumption patterns and opposes waste.

Article 6 It is the common responsibility of the whole society to protect the legitimate rights and interests of consumers. The state encourages and supports all organizations and individuals to conduct social supervision over acts that harm the legitimate rights and interests of consumers. The mass media should do a good job in propaganda to safeguard the legitimate rights and interests of consumers, and conduct public opinion supervision over acts that harm the legitimate rights and interests of consumers.