Help me refactor this Clojure code.

add-phone.clj

(defn add-phone
  "Add a phone number to a given service. There are a few steps we have to take:
    - Validate the service name and token
    - Validate the phone number 
    - Send a text message to the number
    - Store the number in the database
  Arguments:
    request - an authorized HTTP request
  Returns:
    201 Resource Created - phone number added to a service
    400 Bad Request - invalid phone number or bad request"
  [request auth-type]
  (do
    (println "Url requested is " (:request-method request) " " (:uri request))
    (println request)
    (def auth-header ((:headers request) "authorization"))
    (def auth-map (utils/get-auth-header auth-type auth-header))
    (if (model/invalid-user-and-pass auth-map auth-type)
        {:status 401,
         :headers {"WWW-Authenticate" "Basic realm=\"smsauth.herokuapp.com\""}}
      (do
        (def raw-phone-no (:phone_number (:params request)))
        (def service-name (:service-name auth-map))
        (if raw-phone-no
          (do 
            (def valid-phone-no (utils/parse-phone-no raw-phone-no))
            ; XXX get the service id some other way.
            (def service-map (model/service-in-db service-name))
            (def service-id (service-map :id))
            ; XXX check that service doesn't already have phone number
            (model/store-phone-no :numbers service-id valid-phone-no)
            (twilio/send-sms-verify twilio/sms-url valid-phone-no service-name)
            ; XXX jsonify this, send more information, document it.
            {:status 201,
             :body (json/json-str {
                      :service_name service-name,
                      :phone_number valid-phone-no,
                      :status "active",
                      :uri (:uri request)
                      ; should have some kind of unique id for the phone number
                      ; here.
                      ; also return the date
                    })})
          {:status 400,
            :body (json/json-str {:error "Please include a phone_number."})})))))