The attachment looks like your sales invoice? If yes then the sale should be in sales, it does look like it has been duplicated though. This is probably easiest to check by looking at their debtor account (accounts receivable).
Raising a sale invoice only affects cost of sales if you have a items costing system working which I would try to avoid. It works as follows: a supplier invoices you for parts and QBs puts these goods in stock at cost, when you sell the parts QBS raises a sale and reduces the stock automatically via cost of goods sold. So if you bought 10 items at £100 each and sold 8 at £150 then your sales would be £1,200 whilst cost of sales would be £800, the remaining £200 in stock.
If you don't need to job-cost or monitor stock then it is much easier to place the original purchase invoice to costs of sales: purchases instead. Under this method you'd journal in the closing stock figure at the end of the accounting period.
