Deductions & credits

Hi Opus 17,  I filed with no stimulus for 2020 for a refund of ~$6K, about a week later It jumped ~$1.7K without any input from me.  I waited several months before the IRS sent the refund for both the refund plus stimulus.  I didn't know it was a stimulus until I got the letter.  I assume the 1.7k was put in by TurboTax.  Where on line can I get these 1444-1444b letters?  How do I engage the audit defense, I only have the # and the cost but don't know how to contact.  My letter from the Christian attacking IRS implies an audit.

Regards,

Adrian