If it DOESN'T scroll when the batteries are removed from the remote, that points to the remote being the problem. Does the up or down control rocker (whichever way it scrolls) seem to be stuck in the depressed position? If not, the remote could be defective.
Any inexpensive universal remote that says it works with Roku devices could be used to replace your Roku remote.
Meanwhile (or instead if you prefer) if you have a tablet or smart phone connected to your home network you may be able to control your Roku via the Roku app available for Apple and Android devices (while the batteries are out of the remote to prevent the out of control scrolling).
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