please help upgrade from 8.5 to 10.5

hello - i have a problem
im using cubase 8.5 pro education version
excedentlly bought the - Cubase Pro 10.5 Upgrade Cubase Artist -
now it dosnot work after i get the upgrade - and i followed the link - it requerd me to download 21 gb pf cubase 10.5 and now licens dosent match or work… how can i fix this thing - can any boddy support me online or help me whit that?

You have the 8.5 Pro and bought the UPGRADE from 10.5 Artist --> 10.5 Pro.
What you should have bought was the UPDATE from 8.5 Pro --> 10.5 Pro

ok, i now i made a mistake - how can i fix it?

Obviously you need to contact the shop you bought it from, just like in real life.

no onliny sopport? i bouth it via stiberg online shop

Then that is who you need to contact. I believe it recently changed from Asknet to Nexway. Nobody on this users helping users forum can assist you with purchase related questions.