Hello, try one of the following solutions;
Teleport to garage or service.
Sleep at hotel, service, etc.
Use a train or ferry.
If any of those solutions didn't help you, you should reset your economy manually. To do so, please follow this guide;
Go to "My Documents/Euro Truck Simulator/profiles" or “My Documents/American Truck Simulator/profiles” and find your profile - if you only have one profile, it'll be the only one, otherwise, you'll have to work out which one you want to edit.
Open the "config_local.cfg" in the profile folder in your text editor (Notepad,...).
Look for the line 'uset g_force_economy_reset "0"' - change the 0 to 1 and save the file.
Now, start TruckersMP and load your profile. You should receive a message saying "Game change detected". Your economy should have been reset now.
Lastly, exit the game again and change that 1 back to 0 in your "config.cfg", otherwise, it'll reset every time you start the game.
Vİa: https://truckersmp.com/knowledge-base/article/23