I bought Cubase Pro 10 for full price one day before the 50% off promotion started, is there anything I can do?

I just feel so stupid. If I had waited one day longer I could’ve bought it for 50% less. It wasn’t an upgrade from an earlier version, it was the full price product.
Has anyone else been through anything similar before? Is there a grace period for this kind of stuff as well, or is that applicable only for upgrades?