Glad it finally worked out. As you found out, it is best to wait until you have been charged the change fee and then start the process. It is hard to refund something that has not been charged. And sending in info too earlier, makes it too easy for documentation to be misplaced.

Also, there was no need wait for travel to be completed, once the change fee has been paid, the refund can be processed.
The online refund process has a method for electronic submitting documents, no need for a fax machine (also free online "faxes" service exist).

All this is documented on the Refunds web page.