Choosing a solution is the closest you will get to closing it. If someone else responds to it you will get a notification in your email unless you check the box in your community profiles settings turning off email notifications. Note this will also turn off notifications of private messages unless you sort thru your preferences for private messaging notifications.
Pay be by voucher to continue service or reactivate. Then using @dust2dust's suggestions for account recovery or send a private message with " forgot login credentials" in the subject line. You will need an active account to recieve the 2FA text with your verification code for the final step to access your account. You can then disable 2FA verification in your profile page.
The following post contains additional info on vouchers and other alternative methods of payment along with links to customer support.