How to get pages_messaging permission aproved?

Question

I am trying to revive an old Facebook bot. The problem is that I got pages_messaging permission revoked and now the users are not getting replies from the bot. It replies to me, as developer.

I sent request to add this permission but since they cannot test the correct behaviour of the bot (he's not replying to users) they denied the request.

Does anybody have any ideas how to solve this issue?

Thanks!