Earlier this year, the IRS sent millions of U.S. taxpayers letters, telling them they’d made a mistake when they filed their returns — most often something related to COVID relief payments. Last month, the IRS followed up with a second wave of letters that baffled many taxpayers. Some people smelled a scam, but they smelled wrong.

Michael White got one of the approximately 13 million letters the IRS sent out in the spring. The Wisconsin swim coach said it informed him he was getting a smaller relief payment than he’d claimed. OK, he thought. So much for that. Then he got the second letter, last month, which was “really confusing. It made the same claims as the first and I thought the first was saying it was over.”

The IRS is sending out about five million of those confusing second letters. Here’s why: in some of the first letters, it neglected to tell taxpayers they have a right to appeal. That’s all the second letter said. The IRS’s National Taxpayer Advocate, Erin Collins, said you can call the number on the letter to appeal.

“But it’s — right now the IRS is only answering less than 20% of those calls,” Collins said.

She recommended replying with your own letter, certified, of course. So you’ve got documentation to make your case.