Hello! When a user cancels their registration record, the record is NOT erased. It remains but has a status of "Cancelled". You setup per event if the option to cancel is even given and you can give the date/time for a cancellation deadline. After the set date, the cancel option would no longer show up.
You can't setup for full payment to still be due within X days of the event, however a cancellation does NOT automatically refund any payments already made.
You CAN setup a cancellation FEE which would be required to be paid online before the cancellation would be accepted. This might be something to consider. Once the fee is enabled, it doesn't matter what the date is... if they cancel, the fee is applied. You could of course leave the fee disabled, then 5 days before the event, go in and enable it... taking all of 15 seconds
Just giving some ideas and letting you know what type of options are available. Thanks.