No, you can't unlock your number once Viber developers have disabled it. Viber disables numbers and accounts when it suspects they violate the Terms of Service by spamming, virus spreading, hammering, uploading adult content, etc.
However, you have the option of contacting them using the following URL: https://support.viber.com/customer/portal/emails/new
Send the request, and they will check your inquiry. Make sure to use a valid email to receive further details.
