1996 Volkswagen Cabrio AFTER PUTTING FUEL INJECTOR FLUID, I

AFTER PURCHASING FUEL INJECTOR CLEANER FOR MY VEHICLE, I WAITED UNTIL IT WAS TIME TO FILL MY TANK BEFORE USING THE PRODUCT. AFTER PLACING THE FLUID IN MY TANK I FILLED IT WITH GAS, APPROX. 50 MILES AFTER DRIVING MY VEHICLE IT COMPLETLEY STALLED ON ME, FIRST IT STARTED WITH PUTTING, THEN EVENTUALLY STALLED, AND REFUSED TO RESTART. I HAVE SINCE HAD IT A REPAIR SHOP, WHERE THEY HAVE NO CLUE WHAT WENT WRONG. PRIOR TO PLACING THE FLUID IN MY VEHICLE, I HAD 1/4 OF A TANK OF GAS. I THREW AWAY THE BOTTLE AT THE GAS STATION AFTER USE, AND LOST THE RECIEPT TO VERIFY WHICH BRAND WAS USED. FROM WHAT I KNOW THERE WERE NO WARNINGS LISTED, NOR DID MY MACHANIC SAY ANYTHING WOULD HAPPEN OF THIS SORT. HE HAS REPLACED MANY THINGS IN MY ENGINE, NONE FROM THE FUEL SYSTEM, WHICH IS WHERE I'M THINKING THE PROBLEM IS COMING FROM. HE NOW HAS AGREED THAT IT MIGHT BE THE FUEL SYSTEM BUT HES STILL CONFUSED AND IM JUST INPATIENT. WHAT DO I DO?