I was never mailed a PIN and I am meticulous about maintaining any correspondence with the IRS. My 2019 tax return was rejected and I can't use the "Retrieve ID PIN", because I don't have any loans or credit cards except a mortgage. I only bought my house 3 months ago and maybe that is why it doesn't recognize my mortgage account number. They won't mail me another PIN because there is no one at the IRS to answer the phone. I don't know what to do except try to mail it in which could take months to process.
