IRS - Made a Mistake!

I filed my 2014 tax with the aid of a taxprep agency. The agency files free State and Fed returns for people in an income range under $38,000. Everything went through alright to the best of my knowledge. There was a typo on my home address.

I paid the Fed Tax of $34.00 on April 5, the check was cashed April 14. I just got a notice from the IRS on lack of payment. I tried to call the 800 number but what a run, run, run around that was.

I photocopied my cashed personal check and a letter stating it's been paid, you have the funds. This is weird to me. How come they sent such a mistake? It's easy for me to see I paid what was owed on time. The SSN was on the check. I am nervous about an error like this.

The payment address showed only IRS to a city in CA. There was no PO Box or street address. I sent the notice back to the local office in Andover MA.

How could they goof like that? I hope this doesn't turn out to be a fiasco for $34.00.

Last year I filed my sons and then got notice of non-filed. Come to find out his employer had transposed his SS# and I used his W2 to fill out his tax forms. I found it easier to go through the mail than to try on the phone. Even though I had to fill out an amended return (those are even longer and harder to do). It all got sorted out and no fees. IRS doesn't use PO Boxes. Just city and zip. I think they have no problem with stolen mail because who wants to open trouble?