You will not get a refund unless you had originally purchased a refundable ticket. That is why you were given a credit for the cancelled flights (which can not be later exchanged for a refund). The whole point of a credit though is that it can be used towards a future flight.

So if you got a credit for your original, now cancelled flight that you paid ~$1700 for, you could have re-booked your flights for a later date in December (that were $1800) using your credit and paid only ~$100. However, the credit is never for the full amount of your flight because they take off some charges for administrative fees, but still.

Apologies if I've misunderstood your question but your post was incredibly confusing to me.