Cancellation or blockage of ticket

I've been calling and emailing Intercape the entire day with no luck of going through, with a number and email address I found on their website.

I'm supposed to travel Tuesday 30th using their services from Uitenhage to Pretoria. Something urgent has come up, requiring me to stay longer, so I will not be able to travel anymore.

May I please be contacted urgently with regards to cancellation or blockage of ticket to use later.