Did you update?

Well only thing I can suggest is to write support

For iOS:
Go to in-game Settings (top right corner)
1 Tap the SUPPORT tab
2 Choose any topic
3 Choose any topic again
4 Tap on the "Contact Us" (top right corner)
5 Choose a topic related to your issue
6 Fill out the form and hit send

For Android:
Go to in-game Settings (top right corner)
1 Tap the SUPPORT tab
2 Choose any topic
3 Choose any topic again
4 Tap on the speech icon (top right corner)
5 Choose a topic related to your issue
6 Fill out the form and hit send

Don't have access to your device? Check https://socialpoint.helpshift.com/a/monster-legends-mobile/