Sockets server problem

To whomever:
       New person here and I've written a socket server program based on
Scott Klement's tutorial (which is AWESOME!) but am having a problem with
receiving data.   Here's what I am doing:
        I set the socket descriptor (using socket 9700),  set the socket to
be reusable, bind socket (9700), and Listen.  When the client transmits
data to 9700, my program begins a loop to accept and will set up a
secondary socket while it receives the data and does what it wants with it.
Then, when I've finished working with the data, I send an ACK message back
on the secondary socket and close that socket leaving 9700 still open for
another request.  The client says that this shuts their connection to 9700
down.
      At their request, I left each secondary socket open and when they
tried to send a second message during testing, I watched it try to come
over on the first secondary socket.  Then, after awhile, a new secondary
socket was set and the data transmitted on that new secondary socket and I
sent an ACK on that socket.  This, of course, is unacceptable as I would
have all these open secondary sockets sitting there.   I was told that
their program is attempting to find the open socket (which I've closed) and
is going thru several sockets looking for an open one.   Is this right?  Or
am I doing something wrong from my end?
Thanks
Kathy