Soundbar Serial Number Invalid

[Members_BmZgEYI]

Unable to register a serial number for soundbar HW Q990c.  I used the code on box and soundbar - which match allowing for the final digit - but no success.  Helpline hopeless.  Any ideas how to get a valid serial number to claim cashback?

[Gurky]

Add via smart things and grab it off there, least you can also screenshot it