After you file

I filed back in early February.  It was accepted but then when my anticipated refund date came March 10th it went to Topic 152.  I then received a Letter 4464C with a date of March 13th.  It has now been over 60 days and I have tried all tricks to get a real person on the phone at the IRS since it says to call after 60 days if you have not heard from them.  Does anyone know what the heck is going on?  Thanks!