This is an older thread, but I’m reaching out because I had the exact same thing happen to me, with very similar dates. They only decreased my refund by 683 dollars though so I’m not sure if it’s worth appealing. Was curious how it went for you? (How long it took, did you have to travel, other hoops to jump through). Also I’m curious if this has any lasting consequences (does receiving a 106C make you more likely to receive one in the future or be audited in the future) if anyone knows that.
