Emails not being delivered - Will I eventually get it those emails or are they lost for ever

Emails not being delivered - Will I eventually get it those emails or are they lost for ever

So, today I sent an email from my work email address to my Zoho address. This email was sent 3 hours ago and I still haven't received it. This got me thinking of how many other emails that I am unaware of that I have not received? This is a serious problem. Im not saying that I do not receive any emails on my ZOHO account. Im saying that I do not receive some emails. 

This led me to do some searching and I find that there are many ZOHO users who are facing this issue and franking speaking, for an email service provider, this is the worst that can happen. ZOHO has some very good things going for it and Im hoping that the matter is resolved soon. 

For this particular issue, I need the following clarifications:

  1. The emails that I have not received, will they ever be delivered or are they just lost?
  2. Other users have said that there are delays in delivering the emails. Can ZOHO tell us on average, what is the length of these delays? How long are the delays for?
I hope for some clarification soon.

Regards
Vitesh

Note: I have already emailed support in regards to this but haven't heard back from them yet.