According to the IRS you should have an acknowledgement in 4-6 weeks.
What you need to do if you receive a CP-12 notice.
- Review the notice and compare our changes to the information on your tax return.
- If you agree with the changes we made, no response is required.
- You should receive a refund check in 4-6 weeks, as long as you don't owe other tax or debts we're required to collect.
- You may want to correct the copy of your tax return that you kept for your records, but do not send it to us.
- If you don't agree with the changes we made, contact us within 60 days from the date of your notice and see frequently asked questions below.
-follow this link for more information-
Understanding Your CP12 Notice | Internal Revenue Service