Unfairness from Epromo.co.za

I bought two bamboo pillows earlier this year from The Rand Easter Show Epromo Stand for R1000. After trying it out, I found one is softer than the other! I have neck pain through previous injury and thought this was my solution. I really regret buying this as it was uncomfortable for me. The sales person at the Rand Show was very convincing. My husband however is loving his pillow!! I thought mine could be faulty and emailed the company for a refund. I had a very friendly response from the marketing manager, Raymond Moyana and agreed to return the one pillow at his store on the Saturday in Northriding. On that particular day after being told they are open on a Saturday, there was nobody available at the store. Not to mention the fact that I drove for approx one hour trying to locate the shop on the premises! I had driven all the way from Pretoria! After emailing again the marketing manager agreed to refund me R500 after collecting my still brand new pillow. A few weeks later the refund amount in my account was R350 and not R500!! When approached the marketing manager said that his accounts dept said it was a promotion and a single pillow price was R650. So the accounts dept only refunded the difference!!! My argument is, I bought two pillows after being convinced it was a good price. After all of this I still remained polite throughout the entire process! I kept to my promise of returning the imaculate condition pillow but Epromo never stuck to theirs!!! HOW UNFAIR!! I just want my money back please!!! I have been patient and very polite thus far!!!!