Our four brothers 1996 also applied for f4 immigration to the United States. They have received an application for an immigrant visa. Why haven't I received it?

It arrived, but you didn't receive it. Either the consulate staff was negligent or it was lost. What you have to do now is to take out the receipt number of that year and send it to the consulate, or directly ask them to reissue it, and write a bigger contact address, phone number and name to avoid making mistakes again.

Don't worry, people's workload is tens of thousands to hundreds of thousands every year, and mistakes are inevitable. Just watch for yourself.