CP12 letter - in error?

[jyeh74]

The IRS sent a notice decreasing my tax refund by $3165.  I was not sure what this was due to.  It says that tax owed was increased and I reviewed this with my 1040.  The difference between what I was supposed to get vs what the letter stated was $3165.  I looked online and it said that in situations where I changed employers in 2025, look at the W2 box 4 and add up all the numbers.  The former employer had $10,918.20 in box 4 and the new employer had the exact $3165.36 in box 4.  I am the only person listed on the W2.  Did the IRS get confused and think these were the same employer and reduced my refund by this $3165 amount?  Do I do amendment or do I call?  what number

[Bsch4477]

Call the number on your notice.