Help me no command error etc

I recently tried to install a custom ROM in my samsung j6+ but halfway through it my PC turned off.
Then the problem starts i decided to reboot my phone but it shows this error “No command” " #Reboot recovery cause is [[check_bootmode]RebootRecoveryWithKey]#
Block-based OTA
Supported API: 3


E:Failed to mount / cache: Invalid argument

The error message keeps appearing for just a fraction of a second then disappear and appear again

I tried to go to recovery mode but no luck i cant get to it
I drained the battery to turn off the device then go download mode but after get to it, it also keep restarting

help me please. thank you

I think forum is not the right place for this issue. You should consult with customer care, they may help you regarding this. Samsung Developer Forum is for the 3rd party developers. If you face any problem regarding application development you may get help from here.

Thank you.