I purchased the SDX Value Pack from Bestservice.com and registered the serial number I received inside Product Manager. I don’t know whether your system only shows purchases made directly from Toontrack or if it shows purchases from third-party retailers, as well. But I did place the order today and Product Manager accepted the serial number for that order, but then only allowed me to select one expansion pack.
I am new to the forum, but would be glad to send you a copy of the receipt and a screenshot of the serial number I received, if that helps.