Bought a Google Play card

I needed to buy an RTA app that is available on Android and for that, I decided to pay for the app via a Google play card. I bought one worth about $20. All I did was go to the place that was selling it (in my case it was a small provision shop) and told the proprietor that I wanted a $20 Google Play card. So he gets one and scans it into a machine that looked a lot like the NETS terminal that we use to pay via our ATM cards. After that, I took the card and scraped off the part where a number was hidden. This number was typed into the Google Play app on the phone just like that, I got twenty bucks into my Google account. Now…to get me my app…Google