unable to turn room light on all the time
Bryant Low voltage relays are no longer made.  However the GE RR7 is a direct replacement. Google "GE RR7" or talk to an electrical supply house in your area.

Same thing, for the switches.  You probably have Bryant branded low voltage switches (since the relays were Bryant). You can purchase the P&amp;S/Legrand brand for replacements.  Again google to purchase or contact and Electrical Supply house in your area, like the relays these will not be in carried at a big box store.

In your case, the component that likely has gone bad is the relay.  When you push the switch can you hear the relay click even when the light doesn't come on? If so, the switch is working correctly but the relay is not making contact.  On the other hand if there is no noise from the relay then it's likely the switch.  Since your problem is intermittent its not likely there is a wiring issue either on low or line voltage side, it's most likely that the relay contacts just aren't good anymore.