Viacom's stock is tanking because 13 million people are about to lose its channels

Viacom's cable networks are in danger of getting dropped by Dish Networks, and its stock is getting crushed.

The owner of such networks as MTV, Nickelodeon, and Comedy Central launched a website Tuesday to pressure Dish

"We are extremely disappointed that DISH has not engaged in a serious way to reach an agreement for Viacom's number one family of cable networks," said the header on the website Keep Viacom.

Television providers and content producers have contracts in which the cable companies pay content-makers fees in order to carry their channels.

The deal between Viacom and Dish Networks is set to expire Wednesday, meaning that Viacom's channels will go black for Dish subscribers once the deal is up.

According to Bloomberg, Dish's 13 million subscribers have begun to see a crawling message at the bottom of the picture on Viacom networks informing them of the move.

This sort of wrangling between a cable provider and content company is not unprecedented. In fact, Viacom went through a similar battle in 2013 with Time Warner Cable which was resolved without a blackout.

The pressure may have backfired, however, as shares of Viacom dove in trading Tuesday. The stock is down a little more than 8.0% as of 2:08 p.m. ET.