That's a known Roku problem, they won't refund and if you want a replacement you have to mail your stick at your cost even within 30 days. The cables been listed on their site as [out of stock] for a year.
@Dougee
Thanks for the posts.
If you are experiencing an issue with your Roku device and it falls within the normal manufacturers warranty window, can you please provide the serial number of your Roku device from Settings>System>About? I'll be able to assist you further from there.
Thanks,
Danny
Where can I buy the $19.99 long-range wifi cord for the Roku sick?
@NanaAmy49, if you have a model number 3810 or 3811 stick then you can get it here:
https://www.roku.com/products/accessories/usb-power-cable-with-long-range-wifi-receiver