Furious Amazon customers threaten to cancel their Prime membership as website crashes on its biggest shopping day of the year

AP/Joseph Nair

• Amazon's website crashed at the start of Prime Day in the United States.
• Prime Day is one of Amazon's most important shopping holidays of the year.
• Some customers threatened to cancel their Prime membership, which costs $119 annually, after the website crashed.

Furious Amazon customers are threatening to cancel their Prime membership after the retailer's heavily hyped shopping holiday, Prime Day, got off to a rocky start. 

Amazon's website crashed at the start of the holiday, which began at 3 p.m. ET on Monday. Some customers got an error message on the site, while others were directed to an endless loop of pages that advertised promotions without allowing shoppers to add anything to their shopping carts.

"Happy Amazon crash day.... if i can't shop on prime day, guess it's time to cancel that membership," Nick Naugle wrote on Twitter. 

Another customer wrote: "No one even bother with attempting to do shopping right now on @amazon for prime day. The site is has been loading for 20mins #DoBetter."

Here's a roundup of what people are saying on social media: