It sounds like you may have accidentally updated to the demo version of the game. Try backing up your save folder by copying it somewhere else, then uninstall and install the correct game version and copy your save folder back in. That should fix the problem
Here is how to make sure you fix the game completely, if I understand your problem correctly:
1) Right-click on Didnapper 2 in your Itch app's library and select Manage.
2) A window will open with the different version you have or can install. Select Manage again for the version that has all your save files (probably the demo version), and then select "Open folder in explorer".
3) In the Explorer window that opens up, go to the /Didnapper 2/www/save/ folder. This is where your save files are.
4) Copy all the files in the save folder to somewhere else on your computer (this is your backup).
5) If you are not sure if you copied the save files from the right version of the game, do step 2, 3 and 4 again for the other version of the game you have installed, just to be safe.
6) When you are sure that you have backed up all your save files in a safe place, uninstall all versions of Didnapper 2, whether they are demo or not.
7) Install the latest version of the full game.
8) Do step 1, 2 and 3 again to find the save folder of the now fixed Didnapper 2. Copy the old save files you backed up in step 4 or 5 into this save folder.
9) Launch the game. It should be back to normal now.
Please let me know if this solved the problem for you. Also consider joining our public Discord server if you wish to get a quicker response, as both developers and other Didnapper 2 players are online and ready to help in the chatrooms there :)