check customer contact no

app/models/customer.rb

@@ -10,7 +10,7 @@ class Customer < ApplicationRecord
   has_many :sales
 
   validates_presence_of :name, :contact_no, :email #,:card_no
-  validates :contact_no, uniqueness: true, numericality: true
+  validates :contact_no, numericality: true #uniqueness: true,
   validates :email, uniqueness: true,format: { with: /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\z/i, on: :create }
   # validates :card_no, uniqueness: true
   # validates :paypar_account_no, uniqueness: true