Heat the oil in a large skillet and dip the tortillas in the oil on both sides to soften them.
Set aside.
In the same skillet, saute the beef, onion, and garlic until the meat is browned.
Drain off any excess fat and add the refried beans, taco sauce, and olives, stirring to combine.
Divide the meat mixture between the tortillas and roll up.
Place half the enchilada sauce in a 12x8-inch (30x20 cm) baking dish, add the enchiladas seam side down, and pour the remaining enchilada sauce over them.
Cover with aluminum foil and bake in a preheated 350F (180C) oven for 45 minutes.
Remove the foil, sprinkle with the cheese, and bake uncovered until the cheese is melted.