Which camera?
Are you sure the problem is with the last 10-15 frames?
The problem could be due to high shutter speeds. At high shutter speed the gap between the leading and trailing curtain gets increasingly narrow. If the shutter is not well calibrated, the gap could reduce to zero instead, so you get no exposure.
When the camera is empty of film, open the film back and run through the complete range of shutter speeds. Hold the camera up to a light and shoot at the fastest shutter speed. You should see a quick flash of light through the shutter to indicate an "exposure" was made. Repeat with slower shutter speed, you should see the flash through the shutter become brighter and longer.
If the shutter curtains aren't resetting at all when you cock the shutter, the problem is more serious... see how you go.