FedEx is having some serious issues this holiday season. According to a report from the Wall Street Journal, the company announced that some of its packages would be showing up late after heavy storms swept through he Southeast and Midwest. The company was reportedly playing catch-up on Christmas day, finishing its deliveries that were held up by the weather.

FedEx’s main air hub is situated in Memphis, Tenn., which was hit hard by the storms this week. The company has adjusted its operations to respond to the delays caused by the weather, and hoped to minimize customer disruptions as it shifted plans to get the last packages out to customers before the holiday.

According to an email from a company spokesperson, “FedEx is operating with slight delays this morning, but we arte continuing to make adjustments and do everything we can to minimize impact on our customers.” Despite the company’s efforts, backlash against the inconvenience on social media was swift and harsh.

FedEx announced that a number of Express employees would be making deliveries on Christmas Day on a volunteer basis, and customer counters were open in the morning for customers to pick up packages in person. The spokesperson noted that this practice has been ongoing for the past several years.

The company’s main rival, United Parcel Service, is based in Louisville, Ken., and had few of the weather issues experienced by FedEx over the holiday. UPS announced that its operations were running smoothly, and that they would “be working into the evening to get everything delivered today.”

It wasn’t just consumers waiting at home for packages who were angry with the company as a result of the delays. Retailers also complained that FedEx was late delivering packages, which resulted in displeased customers. The company said that if retailers had shipped their packages by the deadlines set forth by FedEx, they would have been delivered in a timely manner.

The mix-up came at a particularly bad time this year, as holiday packages have reached record volumes. With a massive consumer shift to online shopping, delivery companies were already particularly strained. The biggest bump in online shopping this year occurred over the Thanksgiving weekend and subsequent black Friday and cyber Monday deals.

According to a recent study, E-commerce sales rose 11.8 percent between Nov. 26 and Dec. 20, compared with last year’s levels. FedEx, UPS, and the U.S. Postal Service project that almost 1.5 billion packages would be delivered by the end of the holiday season this year.

A report outlining the deadly storms that led to some of the package delays can be found here.