Ohh, this is not good. Is there some 2FA involved?
I mean, I used to do some whole account buys on GAW, in time, where email change was not also possible in a way, that seller disabled 2FA, we used escrow, which gave me his login details after payment and I logged in and enabled 2FA on my phone.
This way, seller lost his access to account forever. He would request new password (had to be jerk for that), but it would render account inaccessible for both sides...because of 2FA set for me only...
Well, there is no 2FA on the account, but anyone hacking into the account must also hack into the email address to be able to do anything. Not unlikely to happen as people who try out the cool SuperQuickProfit.exe posted by some Newbie account is likely to have all of his accounts and passwords exposed, but not everybody falls for such things.
As for you, honestly, why all this extra trouble and risk. Spread your risk and try and build upon mining return instead of risky extra's. Which I'm sure you already do. PBMining pays a good share as long as they don't go poof. No need to sell account. And if return is not good enough, then nothing is, and we're all doomed.