Unfortunately this happens quite a lot, however I am sure peeps will understand that due to the amount of enquiries I receive, I feel obliged to sell to the person who pays first, however I understand how frustrating this can be to the OP.
The person who actually bought them contacted me within 2 minutes of my post.
Also, I received a further 4 enquiries within the next hour of my post.
I usually have more than just 1 item and can usually satisfy demand, however in this instance I only had the one set.
Alex.