Not getting inner values from doPost response

[veneet sayyer]

I am connecting Whatsapp cloud API with Google sheet but am not able to get the inner values from e.postData.contents

function doPost(e) {

  var sayyer = e.postData.contents;

  var ab = JSON.parse(e.postData.contents);

  var ac = JSON.stringify(e.postData.contents);

  var ad =JSON.stringify(ab);

var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Sheet1');

  sheet.appendRow([sayyer,ab,ac]);

}
In the below, all values are actually the same I just edited my id and whatsapp number for security purposes.
var sayyer  = {"object":"whatsapp_business_account","entry":[{"id":"109509497939271","changes":[{"value":{"messaging_product":"whatsapp","metadata":{"display_phone_number":"919464087261","phone_number_id":"100299789543598"},"contacts":[{"profile":{"name":"Veneet Sayyer"},"wa_id":"917697720201"}],"messages":[{"from":"917696250201","id":"wamid.HBgMOTE3Njk2NzgwMjAxFQIAEhgUM0FBNkU3OThERjk2QzU5REZBQUUA","timestamp":"1665641826","text":{"body":"Hj"},"type":"text"}]},"field":"messages"}]}]}

var ab = {entry=[Ljava.lang.Object;@306b568e, object=whatsapp_business_account}

var ac = "{\"object\":\"whatsapp_business_account\",\"entry\":[{\"id\":\"109509491938271\",\"changes\":[{\"value\":{\"messaging_product\":\"whatsapp\",\"metadata\":{\"display_phone_number\":\"919464707261\",\"phone_number_id\":\"100299169583598\"},\"contacts\":[{\"profile\":{\"name\":\"Veneet Sayyer\"},\"wa_id\":\"917696780209\"}],\"messages\":[{\"from\":\"917696780209\",\"id\":\"wamid.HBgMOTE3Njk2NzgwMjAxFQIAEhgUM0FBNkU3OThERjk2QzU5REZBQUUA\",\"timestamp\":\"1665641826\",\"text\":{\"body\":\"Hj\"},\"type\":\"text\"}]},\"field\":\"messages\"}]}]}"

var ad = {"object":"whatsapp_business_account","entry":[{"id":"109509491939271","changes":[{"value":{"messaging_product":"whatsapp","metadata":{"display_phone_number":"919464007261","phone_number_id":"100299169543598"},"contacts":[{"profile":{"name":"Veneet Sayyer"},"wa_id":"917696780201"}],"messages":[{"from":"917696780201","id":"wamid.HBgMOTE3Njk2NzgwMjAxFQIAEhgUM0FCNTBGRjkxNjk1NjcxNERCMkEA","timestamp":"1665642974","text":{"body":"Hsj"},"type":"text"}]},"field":"messages"}]}]}

This is the payload WhatsApp push to google web app webhook- https://developers.facebook.com/docs/whatsapp/cloud-api/webhooks/payload-examples#received-messages

I want values of "wa_id" or "from"

I tried multiple ways but I am not even able to get the value of "entry"
e.postData.contents.entry[0]
e.postData.contents.entry
e.postData.contents[entry]
e.postData.contents['entry']

ad.entry
ad.entry[0]
ad['entry']
ad[entry]

Please help to get this value.

[Clark Lind]

If your post is exact with no typos, then there is something wrong with var ab.     

            \/ opening bracket, but no closing bracket for an array

{entry=[Ljava.lang.Object;@306b568e, object=whatsapp_business_account}

            /\                                                  /\ closing bracket??

Otherwise, I'm sorry I can't help you.