Waltons Stationary (Fourways Crossing) unwilling to rectify their mistake

My daughter attends Reddam House School. Every year we are told to purchase the stationary requirements for the year through Waltons. (We are not given the opportunity to consider alternative companies). We order online using a pre-determined stationary list prepared by Reddam and the goods are delivered to the school. It turns out that this time Waltons messed up the schools order completely. The school received almost double the stationary than what requested for the year. The costs where in excess of R 3000 for a child in grade 2! Fortunately the grade 2 teacher picked up there was a problem and brought this to my attention. I went in store personally on the 24th January 2018 to return the stationary that was not needed. I spent an hour in store going through each item to ensure every item had been correctly captured for refund. I dealt with the manager a Mr. F V. Rooyen (Waltons Fourways Crossing) who assured me the matter would be dealt with and I would receive a refund. I was not given a credit note or any proper acknowledgement of being owed a refund. On my return back to the office I sent Mr. V.Rooyen an e-mail outlining our discussion earlier that day as well as providing him with our banking details. I also asked if he could keep me informed and give me an indication of when I could expect the refund. No response was received. On the 31st of January 2018 I sent a follow up e-mail asking what was happening with my refund. No response was received. To summarise it has been over 2 weeks since I returned the goods and I have yet to receive my refund nor has anybody bothered keeping me informed let alone acknowledging the problem. Waltons have large contracts with the schools where we are not even given the opportunity to consider using alternative service providers (Anti-competitive!) and then mess up the order and take absolutely no responsibility whatsoever! It is disgusting.