Incorrect Promo Date

I am utterly disappointed in the customer service agent that hung up on my calls and failed to assist me. I had trouble making payment for a promo buy one get one free transaction online. I was well aware the promo ended the 22nd, which is why I added the items to the basket 1st thing that day 22nd as the 21st no items were showing. All well was and promotion prices reflected. I then struggled to make payment as I was logging out and struggling to log in continuously. Eventually Got back in and the promotional price was still showing, but disappeared whenever I tried to make payment. Eventually called customer care and was told the promotion has ended, but the promo price showed a minute before I called and I was still in the 22nd promotional end day time frame. I was then told it was while stocks last, there is no stock and I said but the stock is in my basket. What is even more sad, i purchased quite a bit online (one order has yet to arrive) and in store, the 2 items I needed was the matching pieces that only had the correct sizes online. I felt it was very unfair as I was in the promotion time frame and had I have been assisted immediately I would've made payment immediately. Mr P kindly do the right thing and honour those promotional priced until end of day on end date. I have both SKUs and hoping you are willing to assist.