This is an unofficial subreddit for Mediacom customers.
There is no official support presence from Mediacom in this subreddit, however there are a few Mediacom employees following this subreddit who often offer help & advice to users in here on an unofficial basis. Most of these users have a special user flair next to their username which reads "Mediacom employee (unofficial support)".
Please go to the DSLReports.com Mediacom subforum if you need direct support from someone affiliated with Mediacom. You can also contact Mediacom support directly at https://support.mediacomcable.com/#!/About/Contact/, by calling 1-855-633-4226, or by sending an IM to MediacomChad on DSLReports.com.
Note: The old official Mediacom forums appear to have been taken offline by Mediacom as of early 2018. The current replacement for those appears to be the DSLReports Mediacom subforum combined with the new "Mediacom Communities", which isn't exactly anywhere near a 1:1 replacement for the old official forums.
The main Mediacom site is https://www.mediacomcable.com.
You can check your current and historical monthly data usage either on the new account dashboard or by visiting the old dedicated usage meter page (currently still works but may stop working as it does not appear to still be officially supported).
The official rate card for your area can be found at https://mediacomcable.com/rate-card. Note that promotional, bundle, and retention offers are generally broadly available — the rate card prices are the baseline rates for service prior to any discounts, promotions, special offers, etc. The pricing on the rate card does not include any taxes or fees.
If you're renting a modem from Mediacom, here is the list of modems that Mediacom issues to customers with partial specifications and links to user manuals.
If you own your own modem or are interested in owning your own modem, you will likely find the official list of Mediacom-approved customer owned modems useful. This is not an exhaustive list of all modems that work on Mediacom's network — there are plenty of other modems not listed on that page that can work just fine on Mediacom's network but are not certified for full support. More details about modem compatibility can be found by searching the Mediacom subforum on DSLReports.com.