Get Values from Facebook

After integrating the BPCC Agent desktop with facebook in the contact form we use this function $(Contact.messengers) and this is returning a JSON Array in the Agent desktop, i am assuming this is a key value pair sort of thing? do we know how get this value one by one by Index value or hashmap something?

{“type”:“facebook”,“user_id”:“xxxxxxxxx”,“account_id”:"xxxxxxxxx}]

We tried to get the user_id from (Contact.messengers). We used (Contact.messengers[0].user_id) but it still didn’t print out the user_id value.

any thoughts?