Heat the oil and garlic in a non-sticking frying pan and cook for 1 minute until garlic is fragrant; add tomatoes and toss on medium high heat for a couple of minutes until lightly softened. Add olives and thyme leaves and toss to combine. Season with salt and pepper to taste. Discard garlic clove.
In the meantime, cook the tortellini according to package instructions and drain, reserving a ladleful of the pasta cooking water. Add pasta to the pan and stir gently, adding some of the pasta water if you need to loosen the sauce.
Divide Tortelloni among plates and sprinkle with feta cheese, and then serve.