Download link worth it

I'm trying to find the omega force series and I found all the books on the bay but was a bit disappointed with only a few able to get and the rest not downloading

I saw the direct download and I get that it costs money, but is it actually able to download directly or is it like a torrent but from one place

I don't mind paying the $10 to get the one file to get the first 12, I was able to download the last 4

So how does the direct download work?

Thanks in advance