The idea of free shipping is a powerful lure when it comes to joining Amazon Prime. But, who ends up paying the price? In a nutshell, it’s the drivers. Business Insider spoke with 31 current or recently-employed drivers for Amazon, and found out some startling things.

For one thing, drivers described alleged abuses, not to mention missing wages and lack of overtime pay. Many of the drivers also discussed a physically-demanding environment, pressure to drive at high speeds to meet deadlines and even, in some scenarios, not being able to stop to go to the bathroom. Instead, drivers were told to urinate in bottles.

Part of the problem, the article noted, is that Amazon often contracts its delivery services to third-party logistics companies, and doesn’t have much control over the process. The company did indicate, however, that it is working to improve the system. But, the other problem is the customer. Customers are now used to the seamless shopping experience Amazon has created. Noted Tia Koonse with the UCLA Labor Center: “Because it’s this invisible process we, as consumers, are willing to overlook it and what’s happening to the workers.”

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