contract FixedPrice is Initializable, OwnableUpgradeable, ISale {
...
    function _end(Sale memory _sale) internal {
        emit End(_sale);
        ISaleFactory(factory).feeReceiver().transfer(address(this).balance / 20);
-       selfdestruct(_sale.saleReceiver); 
+       sale.finalId = sale.currentId
+       sale.saleReceiver.transfer(address(this).balance);     

    }
