A decent camera....

There seems to be no indication of the original manufacturer.
Anyway, 100 ISO film with (I imagine) a very slow lens and rudimentary shutter would be best in fairly bright conditions, though direct sunlight can produce ugly shadows.

If the results are still bad in well-lit conditions, thenj the processing or, more likely, the camera has a problem (film itself is unlikely to be so bad as to produce the results you describe).
Can you return the camera to the seller if necessary?