Zendesk Support App - Inability to reply to social media tickets

Hello,

We have been using Zendesk Support Suite for a while now and it has been good so far. We have faced an issue that when we reply to social media tickets coming from Facebook Messenger or Instagram Direct using Zendesk Support App (IOS) it does not deliever the messages to the end user.

We can view the reply in Zendesk using the web but once we check our Facebook or Instagram page we cannot find any reply to our customer, however if we replied using the web to reply it gets delivered to the requester.

I have contacted the customer service team and they told me Zendesk Support App is not developed to reply to social media tickets!

Why is it not stated in the features of plans and pricing page? and why do you allow me to view social media tickets in the Support App but do not deliver the reply? Please note that the App does not show that the messages are not delivered and we had to find that out.