Screen Shot 2013-11-29 at 10.48.00 AMLast night and early this morning, Walmart’s website was slammed with the crush of shoppers looking to pick up that company’s Black Friday deals, and it seems that it may be a bit worse for wear.

Sitedown.co, which allows users to submit reports when a website goes down, has registered 180 complaints in the last 24 hours as shoppers have taken to the site to vent their frustrations about their problems with the company’s systems.

In particular, the system the company created for items covered under its “One-hour In-Stock Guarantee” program, which offers shoppers vouchers with codes that can be redeemed for temporarily out-of-stock products, has been experiencing significant delays, with many users on Sitedown reporting that the vouchers aren’t working properly for them.

A Walmart spokesperson told GeekWire in an email that users of the guarantee program are being placed into a “virtual waiting room” and held in a queue so that the company can manage the load of those requests. Users can also return to the site later in the weekend to redeem their voucher.

But it seems like the guarantee redemption system isn’t the company’s only problem, according to this report from an anonymous user at 9:22 a.m. today:

“Attempted to do shopping for my mother last night. It took over TWO HOURS to get items in cart and FINALLY get the checkout page to load. Then the site refused to accept her debit card, telling her to contact the issuing bank on her card. Her card wasn’t the problem. It worked fine at every other online retailer we shopped through. This morning, I attempted once again to purchase a couple of items on the Walmart website. Couldn’t get a single item to go into the shopping cart. I refuse to try any more. I’ll shop with other online retailers that care enough to upgrade servers and keep their site working for their customers!!!!!”

A Walmart spokesperson told AllThingsD that the reports were “isolated incidents,” and that the company was not “seeing any type of systemic checkout issues or outages.”

“We had a great day yesterday, with record traffic volume and nearly 400 million page views,” Dan Toporek, a Walmart spokesperson, said in an email to GeekWire. “The Walmart.com site overall is performing very well.”

By comparison, Amazon didn’t have any complaints listed on SiteDown today, and the online retail giant’s site seems to be working normally.

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