Air Canada
Overcharge from the fight tickte

My mother bought a round-trip ticket for me, on Nov 4, 2011 for round trip form Beijing to Calgary, then she phoned customer services to make a change this round trip from Hong Kong to Calgary and paid for the difference $519 for this round trip change.but on Dec 30, 2011, I reviewed the ticket again, found the the agent only change one-way from Hong Kong to Calgary and didn't changed another way Calgary to Hong Kong (still is to Beijing), but the charge fee is round trip. I had to call customer services again and changed back way from Calgary to Hong Kong and paid extra another $320.I want to the money back for another one way charge $260 that I paid $519 on round trip change Nov 4, 2011.Could you help me? here is the receipt on Nov 4, 2011 attached

Company: Air Canada
Country: Canada
Province: Alberta
City: Calgary

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