just gave 50 to 100 rupees to any filler at station & u r good to go, since 2011 i refill my car from 1 station so everybody knows me over there so for me getting cng is no problem, i just went there gave the key to filler & wait in owner's room max 10 min & refill is done, so buddies solution is stick with 1 cng station make hello, hi to manager, owner, cashier or with 1 filler if u want cng without wait. trust me your investment on cashier, filler will give u output very soon otherwise long wait is compulsory.