Fishy service

This past Sunday on or about 14:00 I drove into BP service station on John Ross Highway Richardsbay for a full tank so I can proceed to Johannesburg. I was driving my 1.2Tsi Volkswagen polo, I pulled up there and asked for a full tank and the attendant did so the pump depicted plus or minus 50l and Plus or minus R750 Of which is fine hence 95 unleaded is cheaper coastal compared to inlands. I then saw the vehicle depicting 440 km to be done by the gas I had in that’s when I inquired from an attendant as to whether he pressed the air lock he said yes , trusting as I then thought upon moving the vehicle will recalculate and depict correct kilos . I drove before I could get into N3 the vehicle from Balfour side the vehicle depicted that I had to refill in the next 60km . I have drove this vehicles for the past 4 years , from Empangeni to JHB I used one full tank and every time when I reach JHB I would be having half tank that I use for local trips . Something fishy happened in that service station, I’ve been trying to contact them since yesterday but the number doesn’t go through.