Hey @Rich841, thanks for getting through to us, welcome to forums and sorry to hear about the difficulty you ran into with being able to continue with your saved progress.
In order to get a better idea of what may be the cause of this, can I check the following with you:
- Did you happen to experience game crash by any chance?
- Are your save files stored locally or is it elsewhere, such as OneDrive for example?
- Where do you have your save files stored?
- Did you try ...