If you’re looking to buy a new phone from AT&T or get an old one fixed, now might not be the time.

Almost 40,000 AT&T employees are striking this weekend after failing to reach an agreement with the No. 2 U.S. wireless carrier on a new contract, according to the Communications Workers of America (CWA) union.

On Friday, workers who are members of CWA walked off the job, the union said. The strike, expected to last until Monday, has already forced retail stores to close, including in Chicago.

Dennis Trainor, vice president of CWA District 1, said AT&T is preventing the “American Dream they once promised.”

“AT&T continues to pinch its workers’ basic needs and stand in the way of high-quality service its customers pay good money for. This is a warning to AT&T: there’s only one way out of this now — a fair contract — and we’ll settle for nothing less,” Trainor said in a statement.

A statement by AT&T Friday called the company a family, adding, “Like any family we have our disagreements, but we’ll sort them out.”

“We’re prepared, and we will continue working hard to serve our customers,” Phil Hayes, an AT&T representative, said in the statement. “A strike is in no one’s best interest, and it’s baffling as to why union leadership would call one when we’re offering terms in which our employees in these contracts — some of whom average from $115,000 to $148,000 in total compensation — will be better off financially.”

A majority of AT&T wireless workers and some wireline and DirecTV technicians are taking part in the strike, the union said. The strike, the first for AT&T wireless, covers 36 states and Washington, D.C.

This comes after four months of bargaining, the union said. The workers are demanding wage increases that cover rising healthcare costs, job security against outsourcing, affordable healthcare and a “fair” scheduling policy.

AT&T workers are expected to picket outside their stores throughout the weekend, including on Michigan Avenue’s Magnificent Mile.