You cannot control everything. You just cannot.

The kosher cellphone market in Israel is already past the tipping point in the Haredi community. i don't think they need to promote it, among the communities that are targeted. Anyone buying a cellphone who pays attention o these things, and unless he has strong needs otherwise, buys a kosher phone. Those who don't want to listen or feel the kosher phone doesn't meet their needs, won't buy it.

Those who feel it is important, such as rabonim and askanim, need to keep it going, but as far as from a promotional perspective we are bombarded far less about it today than we used to be.

Now it seems this is not enough.

until now, people bought the kosher phone, often for social reasons. Schools required it of parents, socially in some places they had to be seen with it, shidduchim, etc. Anybody who was only buying it for social reasons but really wanted a regular smartphone found a solution. Either they would get a second phone, or they'd buy a fake kosher phone, or a dual-sim phone, or some other solution.

Now they want to control the stores even more than before. the stores authorized to sell kosher phones need mashgichim. It has been discovered that these sellers have also been selling treif phones "under the table", and having mashgichim checking the stores will put an end to that.
source: Mynet

It is probably true. Mashgichim checking the stores might be effective and put an end to the under the table black market. But do they really think this will stop the phenomenon of people getting that treif phone they really wanted (out of need or just want)? f they can no longer get it at the local cellphone shop in their own neighborhoods, they'll go out to the adjacent neighborhoods or places further away and find the shops there that sell the phones.

There is no point in having mashgichim check the shops. The people who follow the rules will buy the kosher phones. Th epeople who want to buy the treif phones under the table will continue to find ways to do so.

The only point I see is to give a few more people a parnassa. And at the end of the day, it will be the consumers of the kosher phone market that will be paying for it.

Now, with mashgichim joining the industry, there is probably room for competition at different levels. One hechsher might have a mashhgiach temidi in their stores, while another hechsher might have a mashgiach nichnas v'yotzei...