Why am I unable to change my ई मेल address to one that was used द्वारा an account I deleted?

That's right, I'm outing myself. I the यूज़रनाम change advocate had actually created this account to replace another with a यूज़रनाम I didn't want anymore. The difference is that I'd barely used that account, I hadn't established myself with it and had nothing to lose.

Anyway, that is beside the point.

I'm quite certain I deleted that original account when I created this one but I'm not able to convert the ई मेल address it used to this account as it tells me it's already registered to an account.

I'd let this go for all these years, so why do I care now?

Well, the ई मेल address in सवाल is the one I actively use for communities such as this so it's always been a preference but am also feeling a bit weird since I had to use it when I emailed FP yesterday to see if they take यूज़रनाम change requests.

So I'm figuring it's time to get this figured out.

Any thoughts?