Should I get a refund (AAdvantage Redeposit Fee)?

A while ago, I booked a flight from Toronto – Chicago – Hong Kong – Denpasar on American and Cathay respectively, using AAdvantage miles. Everything was booked in Business. A couple months later, the Toronto – Chicago flight was downgraded to Economy, as there was an aircraft swap to an airplane without Business. American could not put me in Business that day.