Scam: Came across scam today at bpcl petrol

While fueling on bpcl petrol, i was asked to pay first and then they will fill petrol. Felt odd but i did so. Later once fueling was done the meter showed 510 fuel added for my 500 payment. The petrol guy asked me to pay 10 ru more saying it he filled 510 petrol which i denied. Later when i reached mobile i got this message saying that extra 10 ru was free petrol . Petrol worker asked me to pay on different qr code which i denies but i am sure it might have gone to his account So be aware.