Legal analysis: 1. If you don't attend the training, you can ask for a full refund. Although the two sides have not signed any written agreement, it can also be used as a basis if the training school has relevant refund commitments in the publicity advertisements.

2. In view of the fact that training institutions and trainees only issue invoices without signing training agreements, first of all, training activities are contracts for providing labor services. If the training result is agreed, it constitutes a contract, while if the training result is not agreed, only the service process is provided, it constitutes an entrustment contract. If no agreement is signed, it is difficult to judge whether to undertake the contract or entrust the contract, it is difficult to understand the rights and obligations of both parties, and it is difficult to judge the breach of contract and responsibility of both parties. But if the invoice is issued, the training is also an entrustment contract. According to the entrustment contract law, the client has the right to terminate the training contract at will, that is, he can request to terminate the training contract at any time. However, if losses are caused to the trustee, it shall compensate for the losses.

Legal basis: Article 39 of the Law of People's Republic of China (PRC) on the Protection of Consumer Rights and Interests. Disputes between consumers and business operators on consumers' rights and interests can be resolved through the following channels:

(a) negotiated settlement with the operator;

(2) Requesting consumers' associations or other mediation organizations established according to law to mediate;

(three) to complain to the relevant administrative departments;

(four) according to the arbitration agreement reached with the operator, submit it to an arbitration institution for arbitration;

(5) bring a lawsuit to the people's court.