There are various reasons a cancellation could have been rejected, such as: 

1. Inaccurate cancellation effective date 

2. Incorrect mileage (exceeds expiry, same as pricing km, mileage too low, etc) 

3. Invalid lienholder reference number(ex. 1234567, 111111, IDONTKNOW123) 

4. Documentation missing (proof of loss, proof of outstanding loan) 

5. Documentation not valid (wrong VIN, wrong name, etc) 

6. Authorization letter/email from client missing (if a request on an NIDPP was submitted to refund the dealership directly)