From the information provided it appears you have experienced this game save progress lost before so I am assuming when your tablet shuts down unexpectedly (due to no power?), there might have been data corruption occurs to your game save file.
If this 'data corruption' is only local to your device, then there are a number of ways to have your progress restored. Before I go further, may I ask a few questions please?
1. Have you register your email for a gems reward before?
2. Do you know or have you screenshot your original player ID (with the progress of up to Dark Age Night level 19)?
3. Have you got the game installed on another device?
If the answers are yes to all three, I would suggest try deleting the game and do a re-installation followed by an email register with your original email to recover your old account.
1. Yes I have my email registered to get the free gems, but no I can’t log out of it to do it again.
2. No I don’t have a screenshot, I figured that since I didn’t experience any progress issues up until that point, I didn’t need a screenshot, but I guess I was wrong.
3. I don’t have the game on a separate device but I could get it to see if my progress comes back. Reinstalling the game on the tablet gets me to see the same results: no progress and my email is already registered.
If you get the same result on a separate device (using the same registered email address and it offers no previous progress) then your only option now is to contact EA Help Center, open a new case of 'missing content' to get further assistance from the advisors. Hopefully, your current player ID has not been changed and remains the same as the original ID, if this were the case, there is a chance for the advisor to re-link your email to your original game save data on the server, please be aware there might be a long wait and requiring a few email exchanges.
