Did OP try to change the segment before cancelling this is what I meant by the answer on the change cost always surprises me there are all sorts of things that come into play when you do a change including local laws but the reticket desk normally gets it right, but if you skip a segment the airline can cancel everything else in this case the refund is probably correct and op needed to look into the cost of the change once they knew that they needed to change it can be very hard to get something reticked at the airport on a complex fare