I bought a $4000 trip from Expedia, then tried to get a refund about a week afterwards when I found the same flights for $1000 elsewhere. I had to spend 12 hours on the phone with the Expedia reps to get my money back as a credit (only usable through Expedia, for the same airline).
During that time the Expedia reps tried their absolute hardest to get me to stop pursuing a refund by giving me misleading information, long wait times, and occasionally outright lies. I was only able to confirm that a refund was possible thanks to the American Airlines phone reps.
Now, every time I try to use this credit with Expedia, they give me the same runabout for 2 hours. I have been blatantly lied to multiple times in this process regarding: The existence of my Expedia credit, the amount of credit remaining, the eligibility of a certain flight for use with the credit, the credit rollover policy, and American Airlines policy.