Why do I get an email from Intuit notifying me that my 2007 federal tax return has been transmitted and another one stating that it has been accepted.

You will have to contact TurboTax support for assistance with this problem.

See this TurboTax support FAQ for contacting support - https://ttlc.intuit.com/turbotax-support/en-us/help-article/account-management/turbotax-phone-number/L0Od33nMQ_US_en_US?uid=lfgviwbm

Did you check the date sent on them?   Maybe they are old ones that somehow got sorted in your email list and showed up like recent.   I would check with your email provider.  They might have done something that caused them to be sent to you.   Like they restored or resent archived or deleted emails.  They might have had a glitch.  You might not be the only one.