Fixing a duramax losing prime

This truck has been having issues loosing prime since the fuel filter was changed. The truck was towed back to the shop after it wouldn't restart the other day. They "fixed" it and the issues came back the next day. They called the shop this morning and they didnt want to have it towed back to fix it and they told the customer to fi s someone else to fix it and they would reimburse him for it. We went out and got it taken care of him.