What this may be is a breach of contract, actually. Breach of contract may be minor, or material.
A minor breach is substandard performance but one that does not cancel the contract.
A material breach goes to the "heart" of the matter wherein the performance is so bad, or nonexistent, that it validates the other party walking away from the contract.
Is it a minor or material breach? The Court would decide based on the following subjective factors:
1. The extent to which the injured party will be deprived of an expected benefit
2. The extent to which the party can be adequately compensated.
3. The extent to which the breaching party will suffer forfeiture.
4. The likelihood that the breaching party will cure their failure
5. The good faith of the breaching party.
Someone in your situation would file a suit alleging breach of contract seeking to get all or part of the money back due to the course's non-performance as promised (performance being a good review for the test).
Technically, one can throw in the deceptive practices act, but that requires showing malicious intent. Here, it seems more like poor performance, which is a contractual doctrine matter.
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