It's important to remember that the business model of file locker sites like RapidShare and Mega is to convince you to upload your files to their site so that they can monetize access to them. Your access as the original uploader is no exception - if they think they can squeeze a couple dollars/euros/bitcoins out of you through changes like this, they'll do it. If you don't want your files to be held hostage, you should probably consider hosting that has a different business model.