In my experience, the best way to solve an issue of an artist/producer sending an incorrect or unsupported file is to contact them again as soon as you can. Although you could go through the process of trying to solve the problem yourself, using a file converter of some kind makes it easier to go directly to the collaborator to get the correct file format. Even if it inconveniences or annoys the musician you are working with, the easiest way to solve an incorrect file problem is to contact the person who sent you the file.