I have recently bought La Sardina lomography camera and after shooting the film came out blank with some colour stains on it. The film was loaded and rewinded correctly and I don’t really know what to do.
You film has been exposed to light from a source that did not reach the film via the camera's shutter. The darkened edges of the film would not be exposed by taking an image using the camera. Even if your exposure settings completely overexposed the film using the camera's shutter, the edges of the film would not receive any of that light as it is masked by the film gate directly behind the shutter mechanism.