The problem is that usually there is no restriction to play them, i mean anyone can play it even Kids, (If one adult want to lose their money on them there is no problem for me) but kids are different because they are the future of the country and they are developing a really BAD habit that can affect their behavior and economy in the future.
And don't computer games develop bad habits? These slot machines are not much different from them, except for the monetary reward. And children's attitude to money may be somewhat different from adults. I don't intend to justify these children's slot machines, but before blaming only these machines for all possible future problems, without proper research on the impact on the child's psyche, it is a little premature.I am pretty sure that those machines aren't legal but there is much corruption in my country so I bet there is some big fishes making money on bribery allowing that those machines keep working on the corner stores.
The legality of these machines is easy to find out. Open the legal documents regarding gambling and study the information there (prohibition of gambling for minors). Perhaps this will help you find ways to influence the current situation. But it seems to me that these machines are most likely in the gray area of legislation, that is, this is designed in such a way that from a legal point of view this is not gambling.My questions here are the next:
This is the first time I've seen children's slot machines and in my country this is "something unheard of".- Are this problem also exist in your country?
- What recommendations you can give to try to Raise the attention of the authorities?
The authorities only pay attention to things that are being talked about en masse. They will be forced to do so, which means the more publicity the story with children's slot machines gets, the easier it will be to do it. But I don't think it will be that easy.
I am going to check the current legislation of my country on this, because even in Casinos there are some warnings about Gambling and Ludopathy
You are on the right track. You must beat the enemy with his own methods. 
I am not want too much trouble by this because I believe that even the local mafias are involved on this, but in some book I read that the economy is going to be a mess when gambling are in every street of the country.
So, try to do it incognito.