<PAGE>

                                                                   EXHIBIT 10.28

THIS NOTE AND THE SHARES OF COMMON STOCK, PAR VALUE $0.01 PER SHARE, ISSUABLE
UPON CONVERSION HEREOF (COLLECTIVELY, THE "SECURITIES") REPRESENTED BY THIS
CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 (THE
"SECURITIES ACT"), OR APPLICABLE STATE SECURITIES LAWS AND MAY NOT BE OFFERED,
SOLD, PLEDGED, HYPOTHECATED, TRANSFERRED OR OTHER-WISE DISPOSED OF, UNLESS
(I)(A) A REGISTRATION STATEMENT COVERING SUCH SECURITIES IS EFFECTIVE UNDER THE
SECURITIES ACT AND (I)(B) APPLICABLE STATE SECURITIES LAWS HAVE BEEN COMPLIED
WITH, OR (II)(A) THE TRANSACTION IS EXEMPT FROM REGISTRATION UNDER THE
SECURITIES ACT, (II)(B) APPLICABLE STATE SECURITIES LAWS HAVE BEEN COMPLIED WITH
OR AN EXEMPTION FROM SUCH LAWS HAS BEEN MET AND (II)(C) IF THE OBLIGORS SO
REQUEST, A WRITTEN OPINION FROM COUNSEL (WHICH COUNSEL AND OPINION SHALL BE
SATISFACTORY TO THE OBLIGORS) THAT THE CONDITIONS IN (II)(A) AND (II)(B) ABOVE
HAVE BEEN SATISFIED.

THE SECURITIES REPRESENTED BY THIS NOTE ARE SUBJECT TO CERTAIN RESTRICTIONS ON
TRANSFER PURSUANT TO AN AGREEMENT AMONG THE NAMED PAYEE AND THE OBLIGORS. A
COPY OF THE AGREEMENT MAY BE OBTAINED FROM THE OBLIGORS AT THEIR PRINCIPAL
OFFICE, 100 EAST 59TH STREET, NEW YORK, NEW YORK 10022.

                 10.75% UNSECURED CONVERTIBLE PIK NOTE DUE 2011

Dated: April 15, 2002                                                   $860,486

         CoreComm Holdco, Inc., a Delaware corporation ("CoreComm HoldCo") and
CoreComm Limited, a Delaware corporation ("CoreComm" and together with CoreComm
HoldCo, the "Obligors"), hereby, jointly and severally, promise to pay to NTL
Incorporated, a Delware corporation (the "Initial Holder"), or its registered
and permitted assigns (the "Holder"), the principal amount of Eight Hundred
Sixty Thousand Four Hundred Eighty-Six Dollars ($860,486) in U.S. currency, on
April 12, 2011 (the "Maturity Date"), to the extent the principal amount hereof
has not been converted or repaid, subject to the further provisions of this Note
set forth herein which further provisions shall for all purposes have the same
effect as if set forth at this place.

         Interest Payment Dates: October 15 and April 15, commencing October
                                 15, 2002

<PAGE>

                           Definitions. For purposes of this Note, the following
terms shall have the meaning indicated:

                           "Affiliate" means, with respect to any specified
Person, any other Person that directly, or indirectly through one or more
intermediaries, controls, is controlled by, or is under common control with such
specified Person.

                           "Agreement" shall mean the letter agreement entered
into by and among CoreComm, CoreComm Holdco and the Initial Holder, dated April
12, 2001, with respect to the issuance of this Note and other commercial
arrangements.

                           "Board of Directors" shall mean the board of
directors of CoreComm. "Board of Directors" shall also mean the Executive
Committee, if any, of such board of directors or any other committee duly
authorized by such board of directors to perform any of its responsibilities
with respect to this Note.

                           "Business Day" shall mean any day other than a
Saturday, Sunday or a day on which state or federally chartered banking
institutions in New York, New York are not required to be open.

                           "Change of Control" shall mean:

                           (1)      the sale, lease or transfer of all or
                                    substantially all of the assets of CoreComm
                                    to any "person" or "group", within the
                                    meaning of Sections 13(d)(3) and 14(d)(2) of
                                    the Exchange Act or any successor provision
                                    to either of the foregoing, including any
                                    group acting for the purpose of acquiring,
                                    holding or disposing of securities within
                                    the meaning of Rule 13d-5(b)(1) under the
                                    Exchange Act, other than any Permitted
                                    Holder;

                           (2)      any "person" or "group", within the meaning
                                    of Sections 13(d)(3) and 14(d)(2) of the
                                    Exchange Act or any successor provision to
                                    either of the foregoing, including any group
                                    acting for the purpose of acquiring, holding
                                    or disposing of securities within the
                                    meaning of Rule 13d-5(b)(1) under the
                                    Exchange Act, other than any Permitted
                                    Holder, becomes the "beneficial owner", as
                                    defined in Rule 13d-3 under the Exchange
                                    Act, of more than 50% (or more than 25% if
                                    neither George S. Blumenthal or Barclay
                                    Knapp is an executive officer of CoreComm at
                                    such time) of the total

                                       2