Thanks to modern-day technology, drug dealers are finding more progressive ways to serve their customers. Such was the case of Mark Slender, a British drug dealer who pleaded guilty Friday to cocaine possession charges in a Gloucester Crown Court after police discovered customers had been paying for his cocaine through credit card transactions.

Police recovered £5,800 (around $7,500 USD) worth of cocaine – about 56 grams – during a warrant issued raid of Slender’s home in Bishops Cleeve, which led to his arrest on Aug. 19. Slender, 35, admitted to dealing the coke ranging in 83 to 93 percent purity, the highest purity cocaine seizure in Gloucestershire ever, Express UK reported. Authorities also discovered an unreported amount of cash, small zip lock plastic bags and digital scales covered in cannabis and cocaine residue. They found about £10,000 (around $13,000 USD) worth of gold relics in his home.

Perhaps the most interesting discovery was a chip and pin credit card reader, which police found plugged into Slender’s car with nearly £12,000 (about $15,600 in USD) worth of transaction receipts from cocaine purchases. The receipts were dated between March 21 and August 15 and tagged with the phrase, “Cheers, Gup.”

Slender, who also goes by the names Mark Wilson, Guppy and Gup, was sentenced to seven years in prison for possession of class A drugs with intent to supply charges. A court spokesperson said Slender’s case may have been the first documented trial in which a drug dealer used a credit card reader for transactions between customers.

Slender’s sentence comes amid a police crackdown on drugs in Gloucester, Cheltenham and Crawly in the United Kingdom. According to BBC News, authorities raided homes in all three counties and arrested three men and three teenage boys this month on suspicion of distributing class A drugs.