<PAGE>
                                                                   EXHIBIT 99(c)




                                        August 14, 2002


Securities and Exchange Commission
450 Fifth Street, NW
Washington, DC 20549

         Re: Panhandle Pipe Line Company Form 10-Q for the Period Ended
             June 30, 2002

To Whom It May Concern:

         As the Chief Executive Officer and the Chief Financial Officer of
Panhandle Pipe Line Company ("Panhandle"), we are submitting this letter to the
Securities and Exchange Commission to explain the facts and circumstances due to
which the Panhandle's Quarterly Report on Form 10-Q for the period ended June
30, 2002 (the "Report") is not accompanied by a certification from us pursuant
to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002.

         As previously disclosed, the Board of Directors of CMS Energy
Corporation, the parent of Panhandle, has formed a special committee to
investigate matters surrounding round trip trades conducted by CMS Energy's
subsidiary, CMS Marketing, Services and Trading Company. The special committee
has begun but has not yet completed its work.

         Also as previously disclosed, CMS Energy is currently in the process of
restating its 2001 year end balance sheet to adjust for offsetting receivable
and payable amounts of approximately $122 million related to round trip trades,
and restating 2001 revenue and expense of approximately $5 million inadvertently
missed in an earlier reclassification of its 2001 financial statements to
eliminate $4.2 billion that eliminated offsetting revenues and expenses
attributable to other such energy trading transactions (which earlier
reclassification is already reflected in CMS Energy's Annual Report on Form 10-K
for the year ended December 31, 2001). This restatement will also adjust the CMS
Energy 2000 year end balance sheet to eliminate approximately $1 billion of
offsetting revenue and expense in that year. Additional adjustments may be
required as a result of the restatement, the special committee investigation or
the re-audit work described below.

         In addition, as has been previously disclosed, by letter dated June 10,
2002, Arthur Andersen LLP informed the Audit Committee of CMS Energy that, in
light of the uncertainty regarding (a) when the special committee will complete
its work, (b) what the results of that work will be, and (c) whether the special
committee's work will have a related impact on previously stated financial
statements, Arthur Andersen's auditor reports related to the consolidated
financial statements of CMS Energy and subsidiaries as of and for the years
ended December 31, 2000 and 2001 cannot be relied upon. While CMS Energy's new
auditor, Ernst & Young LLP, has commenced its audit work, to the extent
necessary to

<PAGE>
support the CMS Energy's restatement and filing of a 2001 Form 10-K/A, Ernst &
Young has advised CMS Energy that the re-audit work can only be completed
following receipt of certain assurances regarding the results of the special
committee investigation. In addition, while Ernst & Young has initiated its
review of the Panhandle's financial statements in the Report, it cannot complete
that review until the re-audit work of CMS Energy has been completed and
therefore the review required by Section 10-01(d) of Regulation S-X has not been
completed and these statements cannot be represented as fully complying with
Section 13(a) of the Exchange Act.

         In light of the foregoing circumstances, we have not issued a
certification to accompany the Report pursuant to 18 U.S.C. Section 1350, as
adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.


                                        Sincerely yours,

                                        /s/ Christopher A. Helms

                                        Christopher A. Helms
                                        President and Chief Executive Officer

                                        /s/ Gary W. Lefelar

                                        Gary W. Lefelar
                                        Chief Financial Officer





                                        2