Do you have a copy of the ordinance, by chance? Exclusive cable franchises are illegal under federal law. If you're litigious, you might be able to get the ordinance overturned.
"A franchising authority may award, in accordance with the provisions of this subchapter, 1 or more franchises within its jurisdiction; except that a franchising authority may not grant an exclusive franchise and may not unreasonably refuse to award an additional competitive franchise. Any applicant whose application for a second franchise has been denied by a final decision of the franchising authority may appeal such final decision pursuant to the provisions of section 555 of this title for failure to comply with this subsection."
Theoretically, a pre-1992 contract negotiated before the law was passed might still be in effect. In practice, these contracts had 5-10 year terms and expired long ago.
In practice, this meant that the deal with Mediacom was "exclusive" since the market was small enough that no other provider would be willing to roll out the full set of services offered by Mediacom (another provider might have been willing to offer basic services to capture cost-conscious consumers). I'm not sure what the federal law says about this sort of thing.