Archie, which bit of this do you not get???

The emails are always sent if you have the box ticked. It I automatic. Not something I control. While a few people my not be receiving notifications the majority certainly are so it definitely works.
ISP's use independent companies that maintain blacklists etc. to filter incoming mail before it even reaches them (for their own security and reduction of bandwidth).

Your tech guy will not necessarily know where that filter is happening but could possibly inform whoever they use that 87.106.52.106 is a safe address.