diesel is running out, please help

Friends ful the tank last night, I realized that diesel was flowing under the car the next day, then when I lifted the back seat, I saw that diesel accumulated in the samandira section, they went to the service. accumulating, what do you think I need to do the correct service says

Do not believe them, I do it too, nothing has ever happened to me. You'd better go to a master in mind.

If the problem happened after the vehicle was full, they said it might be true.
I put a hose in the tank and draw a little diesel, bring it to the half tank, I think if the problem still continues, go to another place.