It is our mistake in the example, to fix that, please add

use \koolreport\export\Exportable;

to the report SalesPivotExtract class

So it will look like this:

class SalesPivotExtract extends koolreport\KoolReport
{
  use \koolreport\excel\ExcelExportable;
  use \koolreport\export\Exportable;
  ...

We have fixed the example in our online site and here is the result.

I will send you the example in zip through email.

I have sent the example to your email. Please let us know if you need further assistance.