Refund non existant

I went to Coricraft 13 June 2015 and purchased 2 items. A few days later when I checked my invoice I realised they overcharged me for 1 item by R55.00 due to the same item being priced differently. I went back into the store, and was advised that despite the fact that I paid cash for the items, they would refund me on my cheque card but the entry had to be send to head office to be passed. It's now been 5 weeks later and still no refund. I even contacted them on e-mail via their website to investigate with no response whatsoever. Please advise? Why do I as the customer have to follow up if you are not delivering according to your standards?