Amazon can boast that this years Thanksgiving shopping weekend was the best in company history, but they are failing on their one and two-day delivery promise to Prime members, reports Recode. Customers are sharing their complaints on social media, like this exchange between Jamie Williams and Amazon Help on December 3. Williams said delivery time for his package is longer than stated, and Amazon replied that extended delivery times can be expected during the holidays.

On Friday, ABC News reported that Amazon deliveries are back to being on time, but the complaints have continued into this week. Here are several tweets from yesterday. These are just a sampling of customer complaints shared on Facebook and Twitter.

Recode reached out to Amazon last week for their comment. They received this response from an Amazon spokesperson who said the shipping delays are caused by high volumes and winter weather.

We are off to a record-breaking start to the holiday season and on peak shopping days, delivery promises vary and may be longer than normal based on order volume and the fulfillment and delivery capacity available in a given area, said the spokesperson. The winter storms that swept across much of the country at the same time also extended delivery times in some areas. We will work directly with customers who are experiencing an issue with their delivery.

On December 5, Amazon thanked Prime members for making 2019 their best year yet. The post received 1.9K comments. One of the top responses came from Ashley Kremer who posted this response three days ago.

The biggest complaint seems to be that Amazon Prime members pay $119 a year, when paid annually, or $12.99 a month when paid monthly, but members aren’t getting what they are paying – most notably, free shipping. Members also receive dozens of benefits including Prime Video, Amazon Music Unlimited, exclusive savings at Whole Foods market, Prime reading, membership sharing, Amazon photos and more. However, many members sign up for the free shipping. Here are the shipping options currently available with a Prime membership:

• Free two-day shipping on eligible items in the contiguous U.S.
• Free same-day delivery in eligible zip codes
• Free two-hour delivery on thousands of items with Prime Now in eligible zip codes
• Free release-date delivery on eligible pre-order items (like newly released books, movies and video games)
• Free no-rush shipping
• Free weekly delivery on a Prime members selected Amazon Day

What exactly is the problem? Amazon can attribute its shipping problems on a handful of issues. Weather is not something they can control, but that is usually a temporary problem. High demand can be a problem, if Amazon is not prepared for it. Given the success of Amazon Prime Day and past holiday shopping weekends, Amazon should have anticipated the additional volume.

The biggest problem is likely the companys logistics. Amazon is no longer using FedEx. FedEx chose not to renew its ground-shipping contract with Amazon in August, nor did it renew Amazons contract with FedEx Express earlier this year, reports The Verge. Instead, Amazon is working with UPS, the U.S. Postal Service and Amazon Logistics, which is made up of a network of delivery partners. The further away the source gets away from its distribution network, the less control it has and the greater the opportunity for failure.

According to ABC, Amazon plans to spend $1.5 billion during the holiday season to ensure one-day delivery. This includes hiring 200,000 seasonal employees, double the number it hired last year. It is also growing its delivery network by leasing planes, building sorting hubs at airports and allowing contractors to delivery packages on the companys behalf.

Insider Take:

I have been an Amazon Prime member for years but have had my own frustrations with Amazons delivery promises over the last year. Amazon has frequently missed delivery deadlines and even issued a refund for a package it chose not to deliver without notifying me. The deliveries have been so inconsistent I gave up on ordering from Amazon for several months. However, I did make some purchases this holiday season and everything has arrived on time or close to on time. To be fair, there is an Amazon fulfillment center within 5 miles of me and an international airport within 10 miles of me, and we have not had any winter weather so far. Maybe I just got lucky.

I can see why Prime members would be frustrated though, and I, too, would take to social media to voice my concerns if I was not able to resolve those issues directly with the company first (their chat line has been very helpful to me). If Amazon wants to continue to be Prime members go to online retailer, they need to keep their promises or at least lower expectations and be transparent about the problems.