incorrect invoice

I have spent two hours on the maze of phone options; when you are asked for your order number and you give it, it connects to another automated person telling me thank you; goodbye. I recently purchased two laptops which were on sale, but just noticed that I was invoiced the full amount, not the sales price. I am simply trying to speak with soemeone about that. Customer service seems to be non-existent, and will make me reconsider my pruchases from dell for my bsuiness in the future.