Always tell the customer the like it is.
Don't beat around the bush, don't hide the truth.
Your product doesn't support the feature? Just say so!
You plan to support it someday? Just say so!
If you have an realistic timeline in the near future, you can mention it – but it it's far away and likely to get missed anyway, don't mention it.
The worst thing you can do is make a false promise and set expectations that you'll never meet.
The package reached the customer two days late. Usually not a big deal at all. Usually is the key word here. What if the customer planned for the package to reach on their child's birthday and it ended up reaching two days after the birthday party? In this case, it's a pretty big deal that you missed your delivery promise!
There will be many situations where you don't really understand the customer's pain. But it's important to be empathetic towards their pain even if you don't fully understand it.
You know what's better than solving a problem when a customer reaches out? You reaching out to the customer and letting them know that you realized there was a problem and have already fixed it.
If you've identified an issue, be sure to reach out to the customer as soon as possible. Not only will the customer appreciate it, but it's simply the right thing to do.
People live busy lives and may have planned to get back to you “later in the day” but forgot about it. Don't assume that they're ignoring you – it's best to follow up and make sure your message wasn't missed.
It only takes seconds to send a quick note to say “hey, did you get my last message?” .. don't forget this important step.