Legal users of medical marijuana in Canada are more than $500,000 behind on their payments for the ganja, prompting Health Canada to send debt collection agencies after some to recover payment, according to the Canadian Press.

Made legal in 2003, medical marijuana in Canada requires a license from public health agency Health Canada to purchase weed directly from the government. Patients then receive the herb in shipments directly to their homes. Although the drug’s cost is subsidized by the public health department, users still must throw in $5 for a gram of pot, or roughly two joints.

There are currently 739 properly-licensed patients in the program, and of that total, 462 have received “final notices” from the government over late payments. Nearly all of the shipments have ceased for those in arrears, a spokesman told the Canadian Press. Health officials have also sent collection agencies after 29 pot patients, resulting in collections of less than $2,000. 

Typically, the health agency has been giving the grass smokers a 90-day grace period to pay before action is taking. But a recent policy change shifted the window to only 30 days. 

Patients are most often prescribed marijuana to relieve pain and nausea resulting from the treatment of chronic illnesses such as HIV/AIDS or cancer.

The statistics were acquired by the Canadian Press under Canada’s Access to Information Act.