Redeeming Penumbra Purchase

[BryanPope30]

So, I wasn't entirely sure if I needed to post this here or anywhere else because this technically isn't really a 'technical' problem more than it is a general problem...

See, I bought the Digital Download version of the whole series (Overture, Black Plague and Requiem) about 3 years ago and played through the main part of the series until I got to Requiem and put it down for a while. Every now and then I'd play through the first 2 games but only got a part of the way into Requiem before putting the game down again and not playing it for a large span of time.

Recently, though, my hard drive was wiped and I didn't think to save the digital receipt or any proof of purchase beforehand, and now I'm getting that itch to play through the game again, this time seeing how it really ends. I was wondering if there is a way to redeem my purchase and download the game again? I looked on the Frictional site for Penumbra but didn't find anything that would lead to me being able to do that... Will I need to purchase the game again to play it?

Edit: To clarify, I DID save the digital receipt and a few codes here and there, and I had a screenshot of the purchase just in case something went wrong, but it was all deleted along with the rest of my hard drive and I never saved a physical copy of it.