TurboTax/Filed Correctly?

Yikes I need an answer from anyone who actually knows about this from experience or professionally. Hubby and I filed our 2007 taxes via Turbotax (first time w/Turbotax) in March. Found out that we owed and sent completed forms to IRS requesting payments be made. Received reply letters back from IRS approving payments. Just got an email from Turbotax as a "reminder" that one final signed form needs be sent to IRS after IRS approves your tax return - as a reminder ONLY not stated it was not done on our part. Called IRS and they say they have no info. on our 2007 return but the Rep. I spoke to said "Well then you must have filed it in time as you say you did since you received reply correspondence from the IRS." - Not sure what to think. Did we mistakenly forget to send IRS one last signed form? According to our records we have done all that we need to then WHY does IRS not show that we filed yet? Pls keep in mind we have always used H & R Block and first time using Turbotax. Thanks