Just don't use the account or login to https://x10hosting.com/sso/login and wait for it to expire due to inactivity.
I don't know if the staff can do this for you directly but you shouldn't create another thread for this and try to bump it instead.
There's another point. During the migration process, they are not counting the 30-days-of-inactivity period; because many users could be unable to login and that. So maybe it will take more time for an account to be "self-distroyed" because of inactivity.