2014 maxforce 13 stumble

can any one help us out with a serious engine stumble on 3 maxfoce 13s. the company i work for bough 3 new lonestars with this maxforce engine. from day one all 3 of these trucks stumble spit and sputter. when you leaving from a stop sighn sometimes your lucky to make it onto the road beacause it almost quites. these 3 trucks have spent about 45% of there lives in the shop to fix this problem. international has told us that its only us having this problem and theres no fix and to drive on. we have had enough of internationals games and BS. the most resent they claimed our progressove shifting was the problem. they removed it and now the truck is even worse.it stumbles just driving down the road. Does anyone have any advise on what we can do? or if you have heard of this problem?
Thanks

 

o we wernt awear of the law suits. and ours are pre def. we have contacted out international area rep and needless to say hes not welcome on our property. spend that kind of $$ and they treat us like crap. were a small company of 13 trucks so we seem to have no pull. any ideas on who to contact. needless to say the people that are supposed to help us have left us to burn.