NEW YORK (CNNMoney) - Sam's Club shut down multiple locations on Thursday, and some employees and customers say it did so without warning. Walmart, which owns Sam's Club, did not respond to numerous requests for comment. Workers and customers learned about the store closures on the same day Walmart drew praise from the White House for raising pay and giving out worker bonuses because of the new lower corporate tax rate. Customers took to social media with questions about why their local Sam's Club stores were shuttered. Some demanded refunds for their Sam's Club memberships, which cost between $45 and $100. The official Sam's Club Twitter account replied to some questions with a brief statement.