License only valid for Elements 2021?

Hi everyone,

 I'm new to Premiere Elements, so apologise in advance for the noob question.

I downloaded the trial version of Premiere 2020 and loved the workflow, so I clicked "Buy Now" from the application and proceeded to checkout. I didn't realise that I was brought to the checkout page of Elements 2021, so I did the purchase without actually realising it. 

The 2021 license won't work when I try to activate Elements 2020, and I cannot upgrade my Mac OS because of other softwares compability issues.

Is there a way to obtain a license for 2020?

Thank you very much,

regards.