Edit in JSFiddle

  //Configure initial parmeters
     sbjs.init({
          session_length: 1, //session minutes
          referrals: [ //Configure social medium
          {
            host: 'l.facebook.com',
            medium: 'social',
            display: 'facebook.com'
          },
          {
            host: 'web.facebook.com',
            medium: 'social',
            display: 'facebook.com'
          },
          {
            host: 'l.messenger.com',
            medium: 'social',
            display: 'facebook.com'
          },          
          {
            host: 't.co',
            medium: 'social',
            display: 'twitter.com'
          }
        ]
      });
      //Change the phone number depending on the traffic source
      
      changePhoneNumberPage(sbjs.get.current,"businessPhoneNumber");
      
      //trafficSource: sourcebuster object with all the session data
      //numberClassName: CSS class that identify the html elements to change dynamically the phone number
      function changePhoneNumberPage(trafficSource,numberClassName){
        //Get an array of elements to change
        var phoneNumberElement = document.getElementsByClassName(numberClassName);
        //Add the direct traffic phone, this is the default phone number
        changePhoneNumber(phoneNumberElement,"DEFAULT PHONE");
        //Detect social phone number source 
        if(trafficSource.src=="facebook.com"){
          changePhoneNumber(phoneNumberElement,"FACEBOOK SPECIFIC PHONE NUMBER");
        }
        if(trafficSource.src=="twitter.com"){
          changePhoneNumber(phoneNumberElement,"TWITTER SPECIFIC PHONE NUMBER");
        }
        //Detect Google Ads traffic
        if(trafficSource.src=="google" && trafficSource.mdm=="cpc"){
          changePhoneNumber(phoneNumberElement,"ADWORDS SPECIFIC PHONE NUMBER");
        }
        //Detect Adroll traffic
        if(trafficSource.src=="adroll"){
          changePhoneNumber(phoneNumberElement,"ADROLL SPECIFIC PHONE NUMBER");
        }        
        //Detect Google organic traffic
        if(trafficSource.src=="google" && trafficSource.mdm=="organic"){
          changePhoneNumber(phoneNumberElement,"GOOGLE ORGANIC PHONE NUMBER");
        }        
        
        //Detect other organic traffic: Bing, Yandex, Yahoo etc.
        if(trafficSource.src!="google" && trafficSource.mdm=="organic"){
            changePhoneNumber(phoneNumberElement,"OTHER ORGANIC PHONE NUMBER");
        }        
      }
      //phoneNumberElement: array of elements with de CSS class name
      //phoneNumber: Phone number to change
      function changePhoneNumber(phoneNumberElement,phoneNumber){
        for (var i = 0; i < phoneNumberElement.length; i++) {
          //Change the text in every element by the phone number
          phoneNumberElement[i].innerText=phoneNumber;
          //If the element is a link element we add the hyperlink with tel parameter
          if (phoneNumberElement[i].localName=="a"){
              phoneNumberElement[i].href="tel:+"+phoneNumber;
          }
        }
      }

<div class="container">
<h1>Welcome to my Website!</h1>

    <p>Phone number in a span:<span class="businessPhoneNumber">123456789</span></p>
    Phone number in a link:
<a class="businessPhoneNumber" href="tel:+18443326433"> +1 844 332 6433 </a>
</div>