This is a serious problem by the way but no one have had found the best solution to prevent a child being so engaged in technology.
No one can prevent them to engage in technology as the world is already changing to a digital world, but as a parent, we have to be aware of the new technology, adopt with it so we will be able to monitor and prevent our kids in accessing gambling sites or any site that is not yet suitable for their age, with knowledge, you can manage the firewall of your network and block gambling sites, that would easily solve the problem.
The problem nowadays is that parents don't want the responsability of monitoring their children, so they outsource this function to the digital gadgets or to the school members. The result are many children without any guidance, because digital devices and teachers aren't sufficient to replace parents' participation in children's lives.
The excuse is always that parents work too much, have little time to spare with their children. However it doesn't matter at all, since excuses don't solve the issue of a kid who doesn't know what is right or wrong, what he should or shouldn't do because he wasn't taught accordingly by those who generated him. If parents were more participative with their children along the day there would be less problems like gambling addiction in their lives futurely.