Bad service from Expedia in refunding for baggage incorrectly charged.

Expedia have overcharged me for baggage on two flights for my husband and I which we never requested - we only had hand luggage. I have sent at least 16 emails requesting a refund but they simply ignore me even after I sent all the details of our flights. They charged me R1829.26 for a simple booking from Singapore to Siem Reap - overcharged because they charged me for baggage in the hold. My request for a refund has been going on since 6th March 2019 - we flew in February. This is unacceptable and I would like a refund as soon as possible.