Asking more for orderd stock

We brought 8 bottles of Swarland Cuveé Brut for R39.99 the 28th of Dec 2017. We asked to order 20 more bottles. The guy was very helpful and immediatly phone to Witbank branch. We arranged to collect the stock the 3rd of Jan 2018, when we arrive the lady said she forgot to get the order. The 4th of Jan we returned to get the stock, they only managed to get 18 bottles but NOW the price is R62.99 per bottle. The lady refused to give me my order against the price of R39.99. I emailed my complaint the 4th of Jan 2018 to head office, 11 days later NO Response what so ever...