(Dallas, TX) --Southwest Airlines says most customers affected by last month's travel nightmare have received their refunds.According to the company, 90-percent of passengers on canceled flights have gotten their money back, and the remaining ten-percent should be refunded in the next few days. Southwest added that all bags with name tags on them have been returned as well. The Dallas-based airline said it will spend more than a billion dollars on system upgrades to avoid another catastrophe.