@jeetk12345-
If you are still within the 1-year US warranty, see this page for warranty and return information: https://support.roku.com/article/208757058
Otherwise, you may purchase a replacement for your particular Streaming Stick model:
For Streaming Stick 3810/3811: https://www.roku.com/products/accessories/usb-power-cable-with-long-range-wifi-receiver
For Streaming Stick 3820/3821: https://www.roku.com/products/accessories/usb-power-cable-with-long-range-wifi-receiver-streaming-st...
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.".
Ultra 4800 | Streaming Stick 4K+ 3821 | TCL Roku TV 43S245/C107X