Jkizer4890----
Roku doesn't make or sell Roku TVs, they just supply the operating system with Roku functions. Roku TV remotes are provided by the TV manufacturers.
Manufacturer support contacts for Roku TVs can be found in this support post: https://community.roku.com/t5/Manufacturer-Support-Warranty-Resources/Contacting-Support-for-Your-Roku-TV/m-p/698232#M9
You may be able to find a replacement Roku TV remote locally at places like Wal-Mart, Target, Best Buy, etc, as well as Amazon and eBay and the TV manufacturers themselves. Be sure they are remotes for Roku TVs -- Roku player devices use a different set of control commands.
Most (all?) Roku TV manufacturers supply direct line-of-sight infrared remotes. These are not linked to the TV and have no pairing button - they are just point and shoot. (Roku TVs can be used with separately purchased Voice Remotes from Roku, which communicate with the TV via wifi-direct and must be paired with the TV.)
You can test whether an infrared remote is sending signals by pointing it at a digital camera, like the one in a mobile phone or tablet, and pressing buttons on the remote. If the remote is sending signals in response to button presses, they will show as flashes on the camera screen.
Roku TVs from these manufacturers all respond to the same set of IR (infrared) commands and so can be used with remotes for any Roku TV in this group:
Element, Haier, Hitachi, Insignia, JVC, Magnavox, onn, Philips, RCA, Sanyo, TCL, Westinghouse.
Remotes from HiSense and Sharp can only be used with HiSense and Sharp Roku TVs because they issue a different set of IR commands from the other manufacturers. Roku TVs from HiSense and Sharp themselves, though, support both sets of IR commands so they also be used with remotes from either of these two groups of manufactures.
(Thanks to @Tivoburkee for this info)
Also some inexpensive universal remotes may also work for your Roku TV - again, be sure it explicitly says it has codes for Roku TV not just Roku players.