Can't remember email for customer account

I have bought a license a few years ago and got the old 1.4 version which seems to be extremely outdated and I can no longer upload styles like I used to. I'm interested in renewing my license and buying the installation service (because I have no clue what I'd be doing and I don't wanna mess things up) my problem is I can not find out any of my old customer account info I'm not sure if that is needed or if it makes things cheaper by renewing? Anyways I just wanna know if I can create a new customer account and still use it for my site that's listed on the old customer account?

Also will my things on my site be deleted from the update? Like users posts and template tweaks, styles?