Where should I go to find a solution to the dispute that the training institution does not refund the fee?

Consult first, or complain, call 12348, or directly sue.

Article 565 of the Civil Code If one party claims to terminate the contract according to law, it shall notify the other party. When the notice reaches the other party, the contract is terminated; If the notice states that the debtor fails to perform the debt within a certain period of time, the contract will be automatically terminated. If the debtor fails to perform the debt within the time limit, the contract will be terminated at the expiration of the time limit specified in the notice. If the other party disagrees with the termination of the contract, it may request a people's court or an arbitration institution to confirm the validity of the termination of the contract.

If one party brings a lawsuit or applies for arbitration to claim the termination of the contract without notifying the other party, and the people's court or arbitration institution confirms this claim, the contract shall be terminated when a copy of the complaint or arbitration application is served on the other party.