In this case, the repayment of more than 1700 may be due to overdue fees and penalty interest. According to China's laws, the proportion of overdue loan fees and penalty interest is not fixed, which is usually determined by the contract or according to the borrower's breach of contract. Therefore, it is difficult to accurately judge whether this is legal without knowing the specific terms of the contract.

With regard to the definition of usury, if the annual interest rate involved exceeds the upper limit stipulated by Chinese laws (currently 36%), it can be regarded as usury. In this case, if the annualized interest rate exceeds 36% and the overdue fee and penalty interest are not clearly stipulated in the contract, it may constitute usury and there may be legal risks.

Summary: According to the information and conditions provided, it is impossible to accurately judge whether this is legal or usury. I suggest you read the relevant contract terms carefully and consult professional legal advice to get a more accurate answer.