purchase a $260 ticket on CO
couldn't fly
cancelled ticket
told residual value is $160 ($100 fee)
tried to apply this ticket to new ticket (new ticket = $140)

they said I would need to pay a $100 change fee charged on my credit card. Then the $160 would be mailed to me in the form of a cert. So essentially i've paid $100 (as I'm only getting $160 back) + $100 change fee. Total $200. is this correct.

in every other airliine (not familiar with CO), i would be able to apply the $160 towards another ticket with no further charge on my credit card.

please explain