When does IRS knows about the taxes paid online . I got a CP14 notice for the amount that I already paid. Any ideas on how to respond to the CP14 regarding the same?

[Rainman12]

Mail in your proof of payment with response.

[santosh-kuchoor]

Thanks!

[Critter · Accepted solution]

What should I do if I disagree with the notice?

Call us at the toll free number on the top right corner of your notice. Please have your paperwork (such as cancelled checks, amended return, etc.) ready when you call.

https://www.irs.gov/individuals/understanding-your-cp14-notice