Wow, that went surprisingly fast.
I got a shared drive (its another tab in the app).
I removed the seller from the members list and done.
Very easy.
However my only concern is if I get enough time, when the shared drive is deleted to migrate my data.
But I guess this is a small risk to take for 6$ (in my case 7€, seems like I overpayed but hey, I think the seller deserves it)
So, I know I'm a newbie here and I don't care if you believe my post, but at least I got my drive
Thanks seller and have a nice day!