Ripping customers off

I bought tickets with this vendor and tried to change dates days later to which they told me of a ridiculous 25% penalty for changing them. I told them there was no where in their tickets it stated a 25% fee and even scanned the ticket to them to prove it. One of their managers Danielle Prinsloo arrogantly tells me that the rules remain even though that ticket only allows a person to refer to their T&CAs via a website link but that's only after purchasing the ticket. Clearly they are trying to hide this information to customers. I need my full refund and will not rest until I get it back they are a *******, 25% for changing a name or date is too much. If they were honest business people they would allow us an opportunity with the T&Cs and not disguise them.