Indeed, the same they tried with me in April 2018.
The first time, when I ordered a drink, the girl who had asked me to come inside charged me correctly for my beer (I paid in cash) and a drink for the girl, which was not overpriced.
Then they gave me many drinks (free shots).
Then they tried to make me buy another drink for a special price.
Somehow they first produced a receipt with 139 PLN, then they were putting a number 2139 PLN (600 Euro).
Luckily, I left the club after they did not explain me and they were pushing me not to go.