We were afraid to change or cancel our flight after reading the reviews here, but were pleasantly surprised that Flighthub actually processed our cancellation and refunds in a timely manner. That said, the fees were indeed high, but it was something we were aware of right after we bought the tickets (which we regretted immediately) and we were just happy we got some money back. BTW we didn't bother calling after reading the reviews so we messaged them on Facebook and continued via emails.
Bottom line, don't but your tickets here especially if you foresee you'll need to make changes but if you have bought it and want to make changes, don't be put off by these reviews as there are actually successful cases.
To Flighthub, we appreciate the timely response and refund.