I checked the reports from my emial opens for the email I do every week.

Until today, I had 1000+ opens in my email shot free two weeks ago and the week before. I checked today, and this is reduced to 400+.

How can these reported numbers be so unreliable?

None of the numbers seem to be accurate. I had a link in my email last week. The landing page reported 179 visitors, but the email only had 109 clickthroughs. The only route to the landing page was through the email.

I have to seriously look at alternatives, as these numbers are important and do not make any sense.