Congressional Democrats are accusing Amazon of “obstructing” their investigation into the company’s labor practices during severe weather events.Members of the House Committee on Oversight and Reform have sent a letter to Amazon CEO Andy Jassy, saying the company has failed to produce materials requested more than two months ago.The committee, which launched the investigation in late March, gave the Seattle-based e-commerce company a list of materials to hand over by mid-April.But the company “still …