99% of artists signed to record companies dont own their masters, that includes your maddonas , Prince ,Beatles, Michael Jacksons etc....
Its a given that the company own the masters , once you sign a deal everything you record is their property, where artists were getting jerked back in the day was over the publishing royalties....
Simon Cowell made a lot of money when he was a record exec jerking artists over their publishing, same as Puffy....
you are more likely for a record company to give you back masters of unreleased music....once its been released they aint giving you their masters back