Amendment to change Social Security Number

So I have had my greencard for the last 5 years. When I first got the greencard I was told by my local social security office that my children were not allowed to have SS number. 

 

Now 5 years later this has caused me some issues. My kids ITIN numbers had expired and the IRS informed me that they were not allowed to be renewed as they have been valid to get SS numbers since 2014.

 

I went back to the local SS office, gave them a piece of my mind and 2 weeks later they now have socials. 

 

So my question is due to the fact they should have been given ss numbers years ago am i allowed to file an amendment to update the ss numbers?

 

Since 2017 the amount of tax credits were greatly reduced to 500 from 1500. I would like to get the money back i was allowed to claim since this date