BAD ONLINE SERVICE

I had a very bad experience with Edgars online with the 75% sale. I've went in to the website under 75% sales and selected three items. The whole time the prices were the original prices and the pop was the whole time there showing that the 75% will be deducted when checking out. After doing the purchase the 75% discount was not allocated, I logged a call immediately on the 14th of September, only today, two weeks later a mail that states they will refund me the sale amount for two items only, but the one item was not on sale, I know for sure that it was, the system was faulty at time, so how can they be sure it was not part of sale items. Very bad experience.