WhatsApp-cannot delete phone number

I installed & created a WhatsApp account. After using it for a few days, it was not want I wanted & I deleted it. Subsequently, I noticed WhatsApp had created a new phone number for my son (who lives out of the country). I routinely use Vonage to call him as it is free. Now, the "lingering" phone number created by WhatsApp is still in the contacts of both Vonage & the phone contacts. Vonage has assigned this number as he defauth and is a "paid" number. I CANNOT delete this phone number via Vonage contacts or my phone contacts. When I view the contact, the the WhatsApp phone number shows, when I attempt to "edit" the contact, the phone number disappears!!! (this happens on both Vonage AND the phone contacts) I'm have re-installed, attempted to delete & re-enter the contact...no luck..darn WhatsApp number still shows and Vonage continues to attempt to use this number & wants to charge me....

Any suggestions/help would be appreciated!!

Sherry
Verizon Samsung S5/Android

— modified on Oct 18, 2014, 4:53:25 PM