UPS 24Dec13 2
UPS delivery man pushing packages. Reuters

Move over Grinch, there's a new villain who stole Christmas this year and it's the United Parcel Service, or UPS.

Thousands of holiday gifts didn't arrive by Dec. 25 this year after a shipping overload caused UPS -- the nation's largest package delivery service -- to be completely overwhelmed, leaving the bottoms of many Christmas trees bare and customers angry. In an official statement, the UPS said it simply had too many packages to deliver in the short holiday season between Thanksgiving and Christmas.

"The volume of air packages in our system exceeded the capacity of our network, as demand was much greater than the forecast," UPS spokeswoman Natalie Godwin said Tuesday. "As a a result a small percentage of shipments are delayed and will not be delivered today."

The UPS posted a similar message for users on Wednesday on its site, pledging to make "every effort to get packages to their destination."

UPS spokeswoman Natalie Black told Reuters that the high volume mixed with the "recent patches of bad weather" were specifically to blame, adding that the company is doing all it can to deliver the remaining packages.

"For now, UPS is really focused on delivering the remaining packages," Black said. "You might not see trucks, but people are working."

Black said the remainder of the packages should be delivered on Thursday or Friday, and those who were guaranteed Christmas delivery would be refunded.

CNN reported that Amazon customers, in particular, were among those affected after some received emails from about a "failure in the UPS transportation network."

Black said that while the number of packages not delivered to Amazon customers is unknown at the moment, "if customers from Amazon were impacted, we'll work with Amazon to resolve that." Customers who are Amazon Prime members can, according to the $79/year policy, ask for additional refunds and may even receive a free month of Prime, Reuters reported.

But as UPS' shipping overload woes continue, customers took to social media on Wednesday to vent their frustrations about not receiving packages on time for Christmas, using hashtags #UPSsucks and #UPSfail. In many instances, UPS responded and apologized to customers individually.

"You Suck. I hope you lose all your big accounts. Don't make promises you can't keep!!!," wrote Facebook user George Nashif. UPS responded: "Hi George Nashif. I'd like to know why you feel that way & offer a resolution. Please e-mail your contact information along with any tracking number(s) or other concerns you may have to Thanks! ~Elizabeth."

On the other hand, some employees of UPS took to the company's Facebook page to defend their employer, like Misty Fulton, who wrote: "We all work really hard and I think people have too high of expectations."