@dewilson2023 I'm sorry to hear about your situation. Tax topic 151 can also refer to an earned income credit claim, though there are more reasons for you to see this code. I'm not saying that this is the reason but it could be because you claimed your nephews.
My cousin claimed his nephews on his tax return about 4 years ago and got audited. He had to pay back all the money. I'm hoping that this isn't your case but the IRS really does have problems with people claiming kids that don't belong to them.
Do you have a local IRS office? I'm not sure if you will need an appointment or not but I'm thinking that you might be able to get the issue resolved faster by going in (with the letter) to give the documents that they are asking you for. If this isn't the way to go, then just mail the documentation.
I'm wishing you the very best with your taxes and your family situation.
