trying to only return a uniq cust with the minimum distance

haversine.rb

require 'csv'
require 'haversine'

#this could be put into one file, works as is
fib_lat = CSV.read("swfl_fiber_lat.csv")
fib_long = CSV.read("swfl_fiber_long.csv")

#use zip to read both arrays at the same time
fib_coords = fib_lat.map(&:last).zip(fib_long.map(&:last))

#multiple column CSV with customer data, headers turned on
customers = CSV.read("swfl_1a_geocoded.csv", headers:true)

CSV.open('swfl-output-data-within-1mile.csv','w', :write_headers=> true, :headers => ['First Name','Last Name','Latitude','Longitude','Feet to Fiber','Address','City','State','Zip','County','Company','Title Code Description','PrimarySIC6 Description','Business Status Code Description','Phone Number','Tollfree Phonenumber','EmployeeSize Location Description','Sales Volume Location Decode','Telecommunications Expense','Email Address']) do |csv_object|
    fib_coords.each do |fib_lat, fib_long|
        customers.each do |cust|       
            if (Haversine.distance(cust[2].to_f, cust[3].to_f, fib_lat.to_f, fib_long.to_f).to_feet < 5280)
                data_out = ["#{cust[0]},#{cust[1]},#{cust[2].to_f},#{cust[3].to_f}, #{Haversine.distance(cust[2].to_f, cust[3].to_f, fib_lat.to_f, fib_long.to_f).to_feet.round(2)},#{cust[5]},#{cust[6]},#{cust[7]},#{cust[8]},#{cust[9]},#{cust[10]},#{cust[11]},#{cust[12]},#{cust[13]},#{cust[14]},#{cust[15]},#{cust[16]},#{cust[17]},#{cust[18]}"]            
                csv_object << data_out
            end
        end
    end
end