Originally Posted by Often1

But, you say that the carrier emailed you the changes as they occurred. Thus, you already have them. It is also unclear whether the travel agent merely agreed to cancel the flights or to refund the tickets.

If the latter, I would start this process over and submit the documentation demonstrating that the flights were changed and further that the TA has already agreed to refund the ticket.

Successful chargebacks usually depend on proper documentation and, in this case, you should already have all that you need.

Originally Posted by brunos

Might be useful if you gave more info. itinerary, date, TA,...
Have you made a chargeback request to your credit card and what is their response?
Did the flight on the original booking operate?
What is the precise wording of the TA email? Do you have an email from the TA confirming that they ask for a refund?