Grey hound

I bought tickets literally yesterday on the 05/09/2017 to Mpumalanga instead of white river.Yes thats was an error I made,I came to get the exchange done today at a checkers where I bought them,instead greyhound officers were called and told me I cant make the exchange where I bought the tickets instead I must go to their offices in Midrand or Pta. How can one purchase tickets in jhb and then be requested to go do the exhange eles where.Greyhound you need to change your system its unfair and ridiculous