I do understand your point. This offer is not for new customers it is for Digital Cable customers who do not have internet service with us.
Here are the Terms and Restrictions for that offer:
This limited time offer for select Mediacom Digital customers adding Online service may be revoked at any time. The discounted monthly rate for Ultra Internet is valid for 12 months beginning at installation. After 12 months monthly rate will increase by $10. After 24 months, the standard rate in effect will apply. Modem rental is not included in price. Download speeds are “up to” speeds and are not guaranteed and may vary. Customer is responsible for additional customer premise equipment and operating system required for Internet access service. Customers must agree to comply with Mediacom’s applicable subscriber agreements and policies. All rates and services are subject to change. Federal, state and local taxes, governmental regulatory fees and surcharges, if any, are additional. Offers may not be combined with any other offers and are void where prohibited. Offers, packages, prices, specifications, terms and conditions may vary among areas and may change from time to time. Other charges, conditions, requirements and restrictions may apply. Call your local Mediacom office for complete details. Mediacom is a registered trademark of Mediacom Communications Corporation.
Standard installations utilize existing wiring and do not include special wiring work, installation or repair of outlets or any other special installation procedures for which additional charges apply. Mediacom Ultra Internet residential service plan provides a usage allowance of up to 999 Gigabytes per monthly billing cycle. Usage greater than the allowance will result in additional charges of $10, excluding taxes and fees, for every increment of up to 50 additional Gigabytes used. For example, if usage exceeds the allowance by 51 Gigabytes, an additional charge of $20 will result. Usage cannot exceed that of a typical residential customer and must conform to the requirements of the Mediacom Online® Internet Access Service Customer and User Agreement and Mediacom’s Acceptable Use Policy. Usage allowances and Internet speeds are subject to change by Mediacom at any time. Refer to the Additional Terms and Conditions-Monthly Usage Allowance for complete details of the usage allowance.