complaint againest gas station in khammam

Location/place: khammam

Name of company/service: auto lpg gas filling station

sir i have lpg car several times i filled gas in hyd &khammam . when i filled gas in hyd igot 18 km milege, but i filled in khammam station i got jest 10 km milege only why this happens i asked them but they did not given proper answer plz take care that