@shakui 

https:// quickbooks.intuit.com/learn-support/en-uk/other-questions/2004-quickbooks-licence-renewal/00/944588

If Support refused to give you the validation code, you don't have any option but purchasing a new license. You may purchase a one time license of QBD 2019 UK version to upgrade your file than QBD 2021 UK version with the subscription.