Let's start with a set of questions to narrow in on what we're dealing with:  When was the problem first noticed, and how does it manifest?  Can you describe the issue in more detail, please?
assitant
I think the first thing is to tell me exactly what you're trying to do, and where you're having a problem.
assistant
My iPhone won't give me text notifications anymore. Can you help?
user
I can certainly help you troubleshoot this issue, I'd be happy to do that.
assistant
Where do I start?
user