It was withdrawn about five years ago - there isn't really a substitute. You need to look at what the problem is and then find a product that might make a difference or treat it.

I have used Permethrin, which The EU also banned but it is is a lot less noxious than Malathion and just as effective, but only toxic to insects and fish It is still available on Amazon in concentrated form as an insect repellant.

Please be aware that permethrin is highly toxic to bees. Also cats. There is a reason it is banned.