Don't delete them in the first place is all I can offer. When you delete the game folder, you delete the saves. On PC they are luckily backed up on the C: Drive, but on Android they're gone.
It sounds like the save data folder didn't transfer to the new device. If you can hook your phone up to a computer, you can manually move the save onto the computer, then hook up the new phone and transfer it into the same folder location. If not, then bluetooth the two phones to each other, locate the save folder on the old phone, and send via bluetooth to the new device and relocate to the appropriate filepath.