Ryan, don't reply to these people, you are making your self look bad, they are all jumping on the bandwagon and this thread is going off topic.
You need to find that receipt, with out out you won't be able to claim your money back from royal mail if they have lost it. Once you find the receipt go to the post office and get a claim form from them.
If you have sent it when you said you did you have no reason to justify your self to the doubters, just go through the motions with the post office.