I got scammed at the gas station in Sosua going towards Cabarete a few years back. I asked for 3000 pesos worth of gas. I was distracted talking to my passenger in the front seat instead of paying attention to the pump and the attendant. Apparently my vehicle had reached full before the 3000 mark. When I turned to see the progress, he had reset the pump and was standing by it like he was still pumping gas. But there was nothing on the display. Of course he claimed it was now full, but couldnt explain what he was doing.
I took an L that day, and paid the 3000. He taught me a valuable lesson. Pay strict attention to the whole filling process. This thread has reinforced a few things. Make sure they start at zero. Make sure you get the amount you asked for. Assume they will scam given the opportunity. Make sure the numbers are clear, and not defective on the pump. Ive been directed to pumps where it's hard to read the numbers on the display. They use that to their advantage. Get out of the car, and make sure you get what you are paying for, and that the gas cap is put back in place. Make sure they arent filling a gas bottle/can behind your vehicle, instead of your vehicle. Check your change and all receipts ( if paying by card ).