Do a Factory reset and set your Roku TV up again as though it were a new unit. Via your remote, start at the TV's home screen then click Settings/System/Advanced system settings/Factory reset then follow the prompts.
I don't know if it will let you create a new account under the same email address you used before -- you may need to use a different address this time.
If you had any subscriptions through Roku and did not cancel them before deactivating your account, your payments will likely continue. Access to any such channel is most likely tied to the old account that you deactivated, and you probably won't be able to cancel them from your new account. You'll probably have to contact Roku for some help in getting this straightened out.
Roku Community Streaming Expert I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well. If this post solves your problem please help others find this answer by clicking "Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X