Bad Customer Service

I purchase an amplifier via the Makro online exclusive deal on the 6th of October 2018. I made payment and received confirmation via email and sms of my order. Got an email today stating they have made a pricing error and will not be honouring my order. This is really bad customer service, since I paid for the product in full and they accepted the payment and started processing my order. What is even more surprising is the order was placed on Saturday the 6th of October 2018 and they only picked up they had a pricing issue a few days before the product was due to be delivered. Makro will need to honour this deal. I know of no website after purchase/ payment has been made that they do not honour the deal, if this is the case with Makro then it will be my last purchase with them. I also encourage other people not to purchase on their website due to their errors being passed on to the customer.