My husband drives a 28 ft truck It quit today He said it was Spitting and sputtering and cutting out And Quit?

The mechanic at the shop said he had Bad Diesel and Mud in his Fuel Filter and in his fuel pump. We have had it in the shop 3 times in the past 2 weeks for this same problem. But the other mechanic would not listen to us. But today the guy working on the truck said if this was fixed 2 weeks ago it would have not gotten this bad. They said Mud is in the lines now, the fuel pump, the Injectors, and the new fuel filter. So now it is a major fix. The company that the truck is rented from in Lowell got mad because he never watched for bad Diesel. How do you Know when a Store has bad Diesel.