My Listing / Sale have confused me.

[607club]

I have listed "In the Description" - Set of 4 Glasses at a price for all 4, I think. Someone just bought either 1 individual at the $ 115, or, all 4 at $115. The listing shows purchased 1,  3 remaining. 

[ajs_coins_and_alchemy]

You incorrectly put "Quantity 4" in the listing.

You are selling ONE Set of 4. That means Quantity 1. You wrongly entered Quantity 4 when you created the listing, which would imply you have FOUR Sets of 4.

The buyer purchased 1 Set of 4, I would now end the listing as you do not have 3 more sets of 4.

[nobody*s_perfect]

You need to end that listing immediately, because you set it up incorrectly as having 4 sets of 4 glasses.  Your buyer purchased one set of 4.