Two things come to mind:
connection of the remote to the PikTV device; is it set to Bluetooth ?
Sometimes unpairing and pairing the remote helps. This can be accomplished in settings, or by simultaneously pressing 4&6 to unpair, and 7&9 to pair.
Are you having trouble with all channels or just specific channels? Are you logged in?
You can find remote pairing in Settings --> Device settings --> Remotes & Accessories --> TELUS Remote
@NFtoBC was referring to the numbers on your actual remote to pair/unpair 😀. I.e. press the 4&6 buttons on your remote control simultaneously to unpair.
The development team is aware of the issue facing the Pik app Apple TV and not being able to start playing a program from the guide. As a workaround, you should be able to navigate to your channels via the 'Home' tab and 'On Now' row. You can scroll to the right to see what's on on various channels.
I recognize that this is not ideal, but the team is working on fixing it ASAP. Apologies for the inconvenience.