I bought the car with a car loan from Toyota Finance, which is four months overdue, that is, once a month, not four months, and should be returned.
The other party calculated that your previous repayments were on time except for the first installment. This issue has been overdue for 4 months, and then the latest issue is overdue 16 days. This has reached the standard of three months overdue in the contract. Three months overdue does not mean that you have three outstanding issues, and the one that is not returned for three months is also counted.