Here, bags of "yaba" tablets, or methamphetamine mixed with caffeine, are displayed for the media in front of the Narcotics Suppression Division in Bangkok on Feb. 1, 2017. Lillian Suwanrumpha/AFP/Getty Images

An elderly couple living near Melbourne, Australia, mistakenly received millions of dollars of methamphetamine after the package was accidentally sent to them on Wednesday. They then unknowingly signed for 20 kilograms of the drug.

The amount of methamphetamine sent to the pair is believed to be worth $10 million Australian dollars, which is roughly just over $7 million USD, reports CNN. The couple called police after seeing the contents of the package.

"They asked each other if they had ordered anything, and it was quite clear that they hadn't," Detective Acting Senior Sergeant Matthew Kershaw told reporters on Thursday.

READ: British Man Drinks $54,000 Worth Of Liquid Meth: "I Am In Trouble Here. I Am Dying, I Am Dead."

Zhiling Ma, a 21-year-old Melbourne man, has since been arrested. He was charged with trafficking and importing a marketable quantity of a border patrol drug, according to CNN affiliate Nine News.

Detective Kershaw said after the arrest, "It's quite a large find to take off the streets, really. That's 800,000 hits off the street that we've intercepted yesterday which is quite significant."