diff --git a/app/models/bank_transaction.rb b/app/models/bank_transaction.rb
index 4b6b6eda0..0370ad666 100644
--- a/app/models/bank_transaction.rb
+++ b/app/models/bank_transaction.rb
@@ -118,7 +118,7 @@ class BankTransaction < ApplicationRecord
 
   def ref_number_from_description
     (Billing::ReferenceNo::MULTI_REGEXP.match(description) || []).captures.each do |match|
-      break match if match.length == 7 || Registrar.where(reference_no: match).present?
+      break match if match.length == 7 || Billing::ReferenceNo.valid?(match)
     end
   end
 end
diff --git a/app/models/billing/reference_no.rb b/app/models/billing/reference_no.rb
index 263100e79..d164f7565 100644
--- a/app/models/billing/reference_no.rb
+++ b/app/models/billing/reference_no.rb
@@ -7,5 +7,10 @@ module Billing
       base = Base.generate
       "#{base}#{base.check_digit}"
     end
+
+    def self.valid?(ref)
+      base = Base.new(ref.to_s[0...-1])
+      ref.to_s == "#{base}#{base.check_digit}"
+    end
   end
 end