They refuse to pay back pensioners money back

I phone Intercape in January this year to move my parents booking, because my dad got sick. (He has a heart condition). The consultant said that they can either do a refund or give them a voucher, because I could not give them a date for certain I went for the voucher option. My parents are both disabled state pensioners and will not be able to use the voucher. I also have no relatives that will be traveling with Intercape. The reply I got when I wanted to exchange the voucher, because they need their money back was as follow: <br> When you called in to the Callcenter on the 13th January you requested that the ticket be changed to the 6th or 7th Feb 2015. The Consultant whom you spoke to, gave you the option to either refund the tickets less the applicable cancelation fee or to either give your parents a voucher. The voucher is valid for 3 years and it only expires on the 12th Jan 2018. The voucher can be utilise on any of our Routes and can also be given to any other family members or friends. They will require permission from the holders of the voucher to make utilise it ,in order to make a new booking with the voucher. I am not happy with that.