Refused to exhange tickets only to later change their mind later after i have made a purchase .

I bought 2 tickets for The Wizard of Oz show and made a mistake and selected the wrong date .I went to Artscape to try and change the ticket dates (which was two days earlier ).The sales lady Nandipha at Artscape told me the tickets had different prices and the ones i wanted were R80 cheaper and she said this was a downgrade which they are not allowed to do ,i went on to explain to her that the money difference wasnt an issue and that i was willing to sign on paper that i did not want it back all i wanted was tickets for the 1st October instead of the 3rd October and she could not assist .I escalated the matter with Computicket on twitter ,again it was the same story about how they dont do "downgrades" .Because the tickets were a birthday gift i went ahead and bought new tickets for the 1st and called computicket to cancel the initial tickets only to find out that there was a 50% cancellation fee !!!!Just after this amount goes out of my account I get a call from Computicket saying they can change the tickets ,talk about a palava and a bunch of unreasonable idiots .Thanks for the ******* computicket! This is sure the last time im spending my money on any of your shows .Its just that this was a birthday gift and i had to !