To deactivate or remove your account from Viber, the main requirement is your access code, which you received while opening the account. You cannot deactivate your Viber account by sending an email to the support team or their admin. They cannot verify that the owner of the request email and the phone number are the same and true.
If you want to deactivate and remove your account/profile you should select the "More" button and from there you can see the "Deactivate account" button and select it.
Note: If you uninstall the Viber application from your iPhone and again install the app, then your Viber account and profile will be still there present in their servers. So, uninstalling the Viber app will not deactivate your account. You have to deactivate the account first and uninstall the application next. However, if your account is inactive for more than 45 days, then it will be automatically deactivated from their servers.
If you miss your iPhone and regained you number, Then you can again use the same account after installing the app on the same number on new phone.