General Motors is threatening to sue its Canadian auto workers union over a controversial Super Bowl ad that ran last Sunday.

GM isi having a tough time up in Canada these days ever since announcing the closure of its plant on Oshawa, Ontario. What was once a darling company has now turned into a real villain, with both Unifor and the United Auto Workers (UAW) unions calling for a boycott of GM products made in Mexico instead of Canada.

The political strife has gotten so heated that Unifor decided to run an ad during the Super Bowl on Canadian networks that lambasted GM for the Oshawa plant closure. It criticized GM’s decision to move production of vehicles from Canada to Mexico and jabbed the automaker over the $10.8 billion bailout that the Canadian government provided during the 2008 financial crisis.

Called "GM Leaves Canadians Out in the Cold," the 30-second ad paints a pretty grim picture of GM’s corporate greed. "GM, you may have forgotten our generosity, but we'll never forget your greed," the ad concludes.

GM’s Oshawa plant currently builds the Cadillac XTS, Chevy Impala, and both Silverado and GMC Sierra pickups. It employs roughly 2,600 blue collar workers and its loss would devastate the local economy.

RELATED: GM CUTS SEVERAL VEHICLES FROM LINEUP AS THEY CLOSE MULTIPLE PLANTS

However, GM is not happy about the Super Bowl ad. According to Autoblog, GM Canada sent Unifor President Jerry Dias a cease and desist letter stating that the ad sent a deliberately false message to Canadians.

"Unifor knows that GM Canada repaid its 2009 loans in full, and that the restructured GM fulfilled all the terms of its agreements with the Canadian government many years ago,” GM wrote in a statement. “Since 2009, GM Canada has contributed over $100 billion to the Canadian economy including $8 billion invested into worker pensions."

The letter gave Dias a Saturday deadline to remove the ad. So far, the ad continues to air on Canadian cable television networks and remains up on YouTube, where it has so far gained 280,000 views.

Dias issued his own response to GM’s threats: "We stand by the belief that if GM wants to sell here, then it needs to build here, and we will not be intimidated from sharing that message with Canadians in this ad.”

NEXT: GM REVEALS PLANS TO SHUT DOWN MULTIPLE NORTH AMERICAN PLANTS